Phase 1b: terminal tabs, up to 4 split panes, theme/font customization

Terminal.tsx is rebuilt around a reusable TerminalPane component (one
xterm + WebSocket connection each) so a tab can hold 1, 2, or 4 panes
(single / split-2 / 2x2 grid), each independently connectable to any SSH
host. Added a small terminal preferences bar (theme preset, font size,
font family) persisted to localStorage and applied per-pane.

Also fixes two build-time issues surfaced while wiring this up: an unused
parameter in Settings.tsx's fieldsWithJumpHost helper, and a stale
JSX.Element reference that doesn't resolve under this project's tsc -b
project-reference build (replaced with React.ReactElement).

This completes Phase 1b of the Termix migration (see TERMIX_MIGRATION.md).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BbJV5nm8KPVH1oNJYKpnoF

TERMIX_MIGRATION.md

@@ -45,11 +45,13 @@ Rationale for splitting: 1a alone is a real, useful terminal (matches what `/ter
 
 **Status:**
 - ✅ **Phase 1a — done.** `/terminal` is a real interactive SSH terminal: `backend/src/routes/terminal.ts` (WebSocket, connect/input/resize/disconnect over `ssh2`), `backend/src/db/secrets.ts` (shared secret loader), `src/pages/Terminal.tsx` (xterm.js + host picker, reuses ArchNest's existing SSH integrations — no duplicate host table). Verified end-to-end against a real test SSH server. No jump hosts, no tabs/split panes, no OPKSSH, no tmux monitor yet — see 1b/1c below.
-- 🟡 **Phase 1b — in progress.** Done so far:
+- ✅ **Phase 1b — done.**
   - **Jump-host chaining**: an SSH integration's config can carry `jumpHostIntegrationId` referencing another SSH integration. `backend/src/routes/terminal.ts` connects to the jump host first, opens a `forwardOut()` channel to the real target, and connects the target `Client` over that channel (single-hop; mirrors Termix's core mechanism without its multi-hop/credential-sharing complexity). Verified end-to-end with two real test SSH servers (one as jump, one as target).
   - **Host-key verification (TOFU)**: new `ssh_host_keys` table (`backend/src/db/index.ts`) stores a SHA-256 fingerprint per SSH integration on first successful connect; subsequent connects are rejected if the fingerprint changes, via `ssh2`'s `hostVerifier` connect option. No interactive accept/reject-changed-key UI yet — first-use accept-and-store, hard-reject on mismatch. Verified both the accept-on-first-use and reject-on-mismatch paths against a real test server.
   - **Settings UI for multiple SSH hosts**: `src/pages/Settings.tsx` previously could only show/edit one integration per type, which silently broke multi-host SSH. Added a dedicated `SshHostsSection` with its own per-host cards (Save/Test/Delete) and an "Add SSH Host" flow, including a `Jump Host` dropdown populated from the other configured SSH hosts.
-  - Not yet done: tab system + up-to-4 split panes and terminal theme/font customization in `src/pages/Terminal.tsx` — that page is still single-session only.
+  - **Tabs + up to 4 split panes**: `src/pages/Terminal.tsx` rewritten around a `TerminalPane` component (one xterm + WebSocket connection each, reusable). Each tab holds 1/2/4 panes (single / split-2 / 2x2 grid); each pane connects independently to whichever SSH host is clicked while it's focused.
+  - **Terminal theme/font customization**: a preferences bar (theme preset, font size, font family) persisted to `localStorage` (`archnest-terminal-prefs`), applied per-pane on connect.
+  - Verified via a clean production build (`tsc -b && vite build`) — no real browser available in this environment to click through tabs/panes, so this is build/type verification only, not an interactive UI test.
 - ⬜ Phase 1c — not started.
 
 ### Phase 2 — SSH Tunnels (NOT STARTED)

src/pages/Settings.tsx

@@ -398,7 +398,7 @@ function SshHostsSection() {
     setDrafts((prev) => ({ ...prev, [id]: { ...prev[id], [fieldKey]: value } }))
   }
 
-  const fieldsWithJumpHost = (excludeId?: number): FieldDef[] => [
+  const fieldsWithJumpHost = (): FieldDef[] => [
     ...sshFields,
     { key: 'jumpHostIntegrationId', label: 'Jump Host (optional)' },
   ]
@@ -420,7 +420,7 @@ function SshHostsSection() {
     setStatusMsg((prev) => ({ ...prev, [host.id]: '' }))
     try {
       const draft = drafts[host.id] ?? {}
-      const { config, secrets } = buildPayload(fieldsWithJumpHost(host.id), draft)
+      const { config, secrets } = buildPayload(fieldsWithJumpHost(), draft)
       const { integration } = await api.updateIntegration(host.id, { config, secrets })
       setHosts((prev) => (prev ?? []).map((h) => (h.id === integration.id ? integration : h)))
       setStatusMsg((prev) => ({ ...prev, [host.id]: 'Saved' }))
@@ -584,7 +584,7 @@ function SshHostsSection() {
               </div>
             </div>
             <div className="grid grid-cols-3 gap-4">
-              {renderFields(fieldsWithJumpHost(host.id), draft, (k, v) => setDraftField(host.id, k, v), host.id, host, host.id)}
+              {renderFields(fieldsWithJumpHost(), draft, (k, v) => setDraftField(host.id, k, v), host.id, host, host.id)}
             </div>
           </div>
         )
@@ -925,7 +925,7 @@ function AboutSection() {
   )
 }
 
-const sectionComponents: Record<string, () => JSX.Element> = {
+const sectionComponents: Record<string, () => React.ReactElement> = {
   profile: ProfileSection,
   appearance: AppearanceSection,
   integrations: IntegrationsSection,

src/pages/Terminal.tsx

@@ -2,19 +2,84 @@ import { useEffect, useRef, useState } from 'react'
 import { Terminal as XTerm } from '@xterm/xterm'
 import { FitAddon } from '@xterm/addon-fit'
 import '@xterm/xterm/css/xterm.css'
+import { Settings2, Plus, X, Columns2, Grid2x2, SquareSlash } from 'lucide-react'
 import { api, getToken, type Integration } from '../lib/api'
 
 const GOLD = '#C8A434'
 const TEXT_SECONDARY = '#7A7D85'
 
+interface TermTheme {
+  name: string
+  background: string
+  foreground: string
+  cursor: string
+}
+
+const TERM_THEMES: TermTheme[] = [
+  { name: 'ArchNest Dark', background: '#15161A', foreground: '#E8E6E0', cursor: GOLD },
+  { name: 'Matrix', background: '#000000', foreground: '#33FF66', cursor: '#33FF66' },
+  { name: 'Solarized', background: '#002B36', foreground: '#93A1A1', cursor: '#CB4B16' },
+  { name: 'Midnight Blue', background: '#0B1021', foreground: '#C7D3F2', cursor: '#5FA8FF' },
+]
+
+const FONT_SIZES = [11, 12, 13, 14, 15, 16]
+const FONT_FAMILIES = [
+  { name: 'Monospace', value: 'ui-monospace, SFMono-Regular, Menlo, monospace' },
+  { name: 'Fira Code', value: '"Fira Code", ui-monospace, monospace' },
+  { name: 'JetBrains Mono', value: '"JetBrains Mono", ui-monospace, monospace' },
+]
+
+interface TerminalPrefs {
+  themeName: string
+  fontSize: number
+  fontFamily: string
+}
+
+const PREFS_KEY = 'archnest-terminal-prefs'
+
+function loadPrefs(): TerminalPrefs {
+  try {
+    const raw = localStorage.getItem(PREFS_KEY)
+    if (raw) return { ...defaultPrefs(), ...JSON.parse(raw) }
+  } catch {
+    /* ignore malformed local storage */
+  }
+  return defaultPrefs()
+}
+
+function defaultPrefs(): TerminalPrefs {
+  return { themeName: TERM_THEMES[0].name, fontSize: 13, fontFamily: FONT_FAMILIES[0].value }
+}
+
+function savePrefs(prefs: TerminalPrefs) {
+  localStorage.setItem(PREFS_KEY, JSON.stringify(prefs))
+}
+
+interface PaneState {
+  id: number
+  hostId: number | null
+}
+
+interface TabState {
+  id: number
+  name: string
+  panes: PaneState[]
+}
+
+let nextId = 1
+const genId = () => nextId++
+
+function newTab(): TabState {
+  return { id: genId(), name: 'Terminal', panes: [{ id: genId(), hostId: null }] }
+}
+
 export default function Terminal() {
   const [hosts, setHosts] = useState<Integration[]>([])
-  const [activeHostId, setActiveHostId] = useState<number | null>(null)
-  const [connected, setConnected] = useState(false)
-  const containerRef = useRef<HTMLDivElement>(null)
-  const termRef = useRef<XTerm | null>(null)
-  const fitRef = useRef<FitAddon | null>(null)
-  const wsRef = useRef<WebSocket | null>(null)
+  const [tabs, setTabs] = useState<TabState[]>(() => [newTab()])
+  const [activeTabId, setActiveTabId] = useState(() => tabs[0].id)
+  const [activePaneId, setActivePaneId] = useState<number | null>(null)
+  const [prefs, setPrefs] = useState<TerminalPrefs>(loadPrefs)
+  const [showPrefs, setShowPrefs] = useState(false)
 
   useEffect(() => {
     api.listIntegrations().then(({ integrations }) => {
@@ -22,13 +87,224 @@ export default function Terminal() {
     })
   }, [])
 
+  useEffect(() => savePrefs(prefs), [prefs])
+
+  const activeTab = tabs.find((t) => t.id === activeTabId) ?? tabs[0]
+
+  function addTab() {
+    const tab = newTab()
+    setTabs((prev) => [...prev, tab])
+    setActiveTabId(tab.id)
+  }
+
+  function closeTab(id: number) {
+    setTabs((prev) => {
+      const next = prev.filter((t) => t.id !== id)
+      if (next.length === 0) {
+        const t = newTab()
+        setActiveTabId(t.id)
+        return [t]
+      }
+      if (id === activeTabId) setActiveTabId(next[0].id)
+      return next
+    })
+  }
+
+  function updateActiveTab(fn: (tab: TabState) => TabState) {
+    setTabs((prev) => prev.map((t) => (t.id === activeTabId ? fn(t) : t)))
+  }
+
+  function setPaneCount(count: number) {
+    updateActiveTab((tab) => {
+      const panes = [...tab.panes]
+      while (panes.length < count) panes.push({ id: genId(), hostId: null })
+      while (panes.length > count) panes.pop()
+      return { ...tab, panes }
+    })
+  }
+
+  function setPaneHost(paneId: number, hostId: number) {
+    updateActiveTab((tab) => ({
+      ...tab,
+      panes: tab.panes.map((p) => (p.id === paneId ? { ...p, hostId } : p)),
+    }))
+    setActivePaneId(paneId)
+  }
+
+  const paneGridClass =
+    activeTab.panes.length === 1
+      ? 'grid-cols-1 grid-rows-1'
+      : activeTab.panes.length === 2
+        ? 'grid-cols-2 grid-rows-1'
+        : 'grid-cols-2 grid-rows-2'
+
+  return (
+    <div className="flex h-full gap-4">
+      <div className="w-56 shrink-0 overflow-y-auto rounded-lg border border-white/10 bg-white/5 p-3">
+        <p className="mb-2 text-xs font-medium uppercase tracking-wide" style={{ color: TEXT_SECONDARY }}>
+          SSH Hosts
+        </p>
+        {hosts.length === 0 && (
+          <p className="text-xs" style={{ color: TEXT_SECONDARY }}>
+            No SSH integrations configured. Add one in Settings → Integrations.
+          </p>
+        )}
+        <div className="flex flex-col gap-1">
+          {hosts.map((h) => (
+            <button
+              key={h.id}
+              onClick={() => activePaneId !== null && setPaneHost(activePaneId, h.id)}
+              className="rounded-md px-2 py-1.5 text-left text-sm transition-colors"
+              style={{
+                background: activeTab.panes.find((p) => p.id === activePaneId)?.hostId === h.id ? 'rgba(200,164,52,0.15)' : 'transparent',
+                color: activeTab.panes.find((p) => p.id === activePaneId)?.hostId === h.id ? GOLD : '#E8E6E0',
+              }}
+            >
+              {h.name}
+            </button>
+          ))}
+        </div>
+        <p className="mt-3 text-[11px]" style={{ color: TEXT_SECONDARY }}>
+          Click a pane, then a host to connect it.
+        </p>
+      </div>
+
+      <div className="flex min-w-0 flex-1 flex-col gap-2">
+        <div className="flex items-center gap-2">
+          <div className="flex flex-1 items-center gap-1 overflow-x-auto">
+            {tabs.map((tab) => (
+              <div
+                key={tab.id}
+                onClick={() => setActiveTabId(tab.id)}
+                className="flex shrink-0 cursor-pointer items-center gap-2 rounded-md px-3 py-1.5 text-xs"
+                style={{
+                  background: tab.id === activeTabId ? 'rgba(200,164,52,0.15)' : 'rgba(255,255,255,0.04)',
+                  color: tab.id === activeTabId ? GOLD : '#E8E6E0',
+                }}
+              >
+                {tab.name}
+                <X
+                  size={12}
+                  onClick={(e) => {
+                    e.stopPropagation()
+                    closeTab(tab.id)
+                  }}
+                />
+              </div>
+            ))}
+            <button onClick={addTab} className="shrink-0 rounded-md p-1.5" style={{ color: TEXT_SECONDARY }} title="New tab">
+              <Plus size={14} />
+            </button>
+          </div>
+
+          <div className="flex items-center gap-1">
+            <button onClick={() => setPaneCount(1)} className="rounded-md p-1.5" style={{ color: activeTab.panes.length === 1 ? GOLD : TEXT_SECONDARY }} title="Single pane">
+              <SquareSlash size={14} />
+            </button>
+            <button onClick={() => setPaneCount(2)} className="rounded-md p-1.5" style={{ color: activeTab.panes.length === 2 ? GOLD : TEXT_SECONDARY }} title="Split 2">
+              <Columns2 size={14} />
+            </button>
+            <button onClick={() => setPaneCount(4)} className="rounded-md p-1.5" style={{ color: activeTab.panes.length === 4 ? GOLD : TEXT_SECONDARY }} title="Split 4">
+              <Grid2x2 size={14} />
+            </button>
+            <button onClick={() => setShowPrefs((v) => !v)} className="rounded-md p-1.5" style={{ color: showPrefs ? GOLD : TEXT_SECONDARY }} title="Terminal preferences">
+              <Settings2 size={14} />
+            </button>
+          </div>
+        </div>
+
+        {showPrefs && (
+          <div className="flex items-center gap-4 rounded-lg border border-white/10 bg-white/5 px-3 py-2 text-xs" style={{ color: '#E8E6E0' }}>
+            <label className="flex items-center gap-2">
+              Theme
+              <select
+                value={prefs.themeName}
+                onChange={(e) => setPrefs((p) => ({ ...p, themeName: e.target.value }))}
+                className="rounded-md border border-white/10 bg-transparent px-2 py-1"
+              >
+                {TERM_THEMES.map((t) => (
+                  <option key={t.name} value={t.name}>
+                    {t.name}
+                  </option>
+                ))}
+              </select>
+            </label>
+            <label className="flex items-center gap-2">
+              Font Size
+              <select
+                value={prefs.fontSize}
+                onChange={(e) => setPrefs((p) => ({ ...p, fontSize: Number(e.target.value) }))}
+                className="rounded-md border border-white/10 bg-transparent px-2 py-1"
+              >
+                {FONT_SIZES.map((s) => (
+                  <option key={s} value={s}>
+                    {s}px
+                  </option>
+                ))}
+              </select>
+            </label>
+            <label className="flex items-center gap-2">
+              Font
+              <select
+                value={prefs.fontFamily}
+                onChange={(e) => setPrefs((p) => ({ ...p, fontFamily: e.target.value }))}
+                className="rounded-md border border-white/10 bg-transparent px-2 py-1"
+              >
+                {FONT_FAMILIES.map((f) => (
+                  <option key={f.name} value={f.value}>
+                    {f.name}
+                  </option>
+                ))}
+              </select>
+            </label>
+          </div>
+        )}
+
+        <div className={`grid min-h-0 flex-1 gap-2 ${paneGridClass}`}>
+          {activeTab.panes.map((pane) => (
+            <TerminalPane
+              key={pane.id}
+              hostId={pane.hostId}
+              hosts={hosts}
+              prefs={prefs}
+              active={pane.id === activePaneId}
+              onFocus={() => setActivePaneId(pane.id)}
+            />
+          ))}
+        </div>
+      </div>
+    </div>
+  )
+}
+
+function TerminalPane({
+  hostId,
+  hosts,
+  prefs,
+  active,
+  onFocus,
+}: {
+  hostId: number | null
+  hosts: Integration[]
+  prefs: TerminalPrefs
+  active: boolean
+  onFocus: () => void
+}) {
+  const [connected, setConnected] = useState(false)
+  const containerRef = useRef<HTMLDivElement>(null)
+  const termRef = useRef<XTerm | null>(null)
+  const fitRef = useRef<FitAddon | null>(null)
+  const wsRef = useRef<WebSocket | null>(null)
+  const lastHostIdRef = useRef<number | null>(null)
+
   useEffect(() => {
     if (!containerRef.current) return
+    const theme = TERM_THEMES.find((t) => t.name === prefs.themeName) ?? TERM_THEMES[0]
     const term = new XTerm({
       cursorBlink: true,
-      fontSize: 13,
-      fontFamily: 'ui-monospace, SFMono-Regular, Menlo, monospace',
-      theme: { background: '#15161A', foreground: '#E8E6E0', cursor: GOLD },
+      fontSize: prefs.fontSize,
+      fontFamily: prefs.fontFamily,
+      theme: { background: theme.background, foreground: theme.foreground, cursor: theme.cursor },
     })
     const fit = new FitAddon()
     term.loadAddon(fit)
@@ -44,11 +320,22 @@ export default function Terminal() {
       term.dispose()
       wsRef.current?.close()
     }
-  }, [])
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [prefs.themeName, prefs.fontSize, prefs.fontFamily])
 
-  function connect(hostId: number) {
+  useEffect(() => {
+    fitRef.current?.fit()
+  })
+
+  useEffect(() => {
+    if (hostId === null || hostId === lastHostIdRef.current) return
+    lastHostIdRef.current = hostId
+    connect(hostId)
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [hostId])
+
+  function connect(id: number) {
     wsRef.current?.close()
-    setActiveHostId(hostId)
     setConnected(false)
     const term = termRef.current
     if (!term) return
@@ -61,7 +348,7 @@ export default function Terminal() {
     wsRef.current = ws
 
     ws.onopen = () => {
-      ws.send(JSON.stringify({ type: 'connect', integrationId: hostId, cols: term.cols, rows: term.rows }))
+      ws.send(JSON.stringify({ type: 'connect', integrationId: id, cols: term.cols, rows: term.rows }))
     }
     ws.onmessage = (event) => {
       const msg = JSON.parse(event.data)
@@ -88,44 +375,22 @@ export default function Terminal() {
     })
   }
 
-  return (
-    <div className="flex h-full gap-4">
-      <div className="w-56 shrink-0 overflow-y-auto rounded-lg border border-white/10 bg-white/5 p-3">
-        <p className="mb-2 text-xs font-medium uppercase tracking-wide" style={{ color: TEXT_SECONDARY }}>
-          SSH Hosts
-        </p>
-        {hosts.length === 0 && (
-          <p className="text-xs" style={{ color: TEXT_SECONDARY }}>
-            No SSH integrations configured. Add one in Settings → Integrations.
-          </p>
-        )}
-        <div className="flex flex-col gap-1">
-          {hosts.map((h) => (
-            <button
-              key={h.id}
-              onClick={() => connect(h.id)}
-              className="rounded-md px-2 py-1.5 text-left text-sm transition-colors"
-              style={{
-                background: activeHostId === h.id ? 'rgba(200,164,52,0.15)' : 'transparent',
-                color: activeHostId === h.id ? GOLD : '#E8E6E0',
-              }}
-            >
-              {h.name}
-            </button>
-          ))}
-        </div>
-      </div>
+  const host = hosts.find((h) => h.id === hostId)
 
-      <div className="flex min-w-0 flex-1 flex-col rounded-lg border border-white/10 bg-[#15161A] p-2">
-        <div className="mb-2 flex items-center gap-2 px-1 text-xs" style={{ color: TEXT_SECONDARY }}>
-          <span
-            className="inline-block h-2 w-2 rounded-full"
-            style={{ background: connected ? '#2ECC71' : '#7A7D85' }}
-          />
-          {activeHostId ? (connected ? 'Connected' : 'Disconnected') : 'Select a host to connect'}
-        </div>
-        <div ref={containerRef} className="min-h-0 flex-1" />
+  return (
+    <div
+      onClick={onFocus}
+      className="flex min-w-0 min-h-0 flex-col rounded-lg p-2"
+      style={{
+        backgroundColor: '#15161A',
+        border: active ? `1px solid ${GOLD}` : '1px solid rgba(255,255,255,0.1)',
+      }}
+    >
+      <div className="mb-2 flex items-center gap-2 px-1 text-xs" style={{ color: TEXT_SECONDARY }}>
+        <span className="inline-block h-2 w-2 rounded-full" style={{ background: connected ? '#2ECC71' : '#7A7D85' }} />
+        {host ? (connected ? `Connected — ${host.name}` : `Disconnected — ${host.name}`) : 'Select a host to connect'}
       </div>
+      <div ref={containerRef} className="min-h-0 flex-1" />
     </div>
   )
 }