feat(v0.3): M3 themes/font settings + M7 session dashboard

- M3: settings.ts (⚙ panel: dark/light/solarized theme + font size A-/A+),
  persisted to localStorage; terminal-session.applyTheme; TabApp.applySettings
  applies to all + new tabs
- M7: dashboard.ts (▦ overlay listing every tab with connection dot + folder +
  Claude status; click a row to focus; live re-render while open);
  TabApp.snapshot()/focusTab()
- Browser-verified: light theme renders + persists; dashboard lists tabs and
  focuses on click. 208 tests green, typechecks + build ok.

public/dashboard.ts

@@ -0,0 +1,94 @@
+/**
+ * public/dashboard.ts — all-sessions overview (M7).
+ *
+ * A ▦ toolbar button opens an overlay listing every tab with its connection
+ * dot, folder name, and Claude status; click a row to focus that tab. While
+ * open it re-renders every second so statuses stay live.
+ */
+
+export interface TabInfo {
+  idx: number
+  title: string
+  conn: string // SessionStatus
+  claude: string // ClaudeStatus
+  active: boolean
+  pending: boolean
+}
+
+export interface DashboardHooks {
+  snapshot: () => TabInfo[]
+  focus: (idx: number) => void
+}
+
+function claudeText(claude: string): string {
+  if (claude === 'working') return '⚙ working'
+  if (claude === 'waiting') return '⏳ needs approval'
+  if (claude === 'idle') return '✓ idle'
+  return ''
+}
+
+export function mountDashboard(toolbar: HTMLElement, hooks: DashboardHooks): void {
+  const overlay = document.createElement('div')
+  overlay.id = 'dashboard'
+  overlay.style.display = 'none'
+
+  const card = document.createElement('div')
+  card.className = 'dash-card'
+  overlay.appendChild(card)
+  document.body.appendChild(overlay)
+
+  let timer: ReturnType<typeof setInterval> | null = null
+
+  const render = (): void => {
+    card.replaceChildren()
+    const title = document.createElement('div')
+    title.className = 'dash-title'
+    title.textContent = 'Sessions'
+    card.appendChild(title)
+
+    for (const t of hooks.snapshot()) {
+      const row = document.createElement('div')
+      row.className = t.active ? 'dash-row active' : 'dash-row'
+
+      const dot = document.createElement('span')
+      dot.className = `tab-dot dot-${t.conn}`
+      const name = document.createElement('span')
+      name.className = 'dash-name'
+      name.textContent = t.title
+      const claude = document.createElement('span')
+      claude.className = t.pending ? 'dash-claude pending' : 'dash-claude'
+      claude.textContent = claudeText(t.claude)
+
+      row.append(dot, name, claude)
+      row.addEventListener('click', () => {
+        hooks.focus(t.idx)
+        hide()
+      })
+      card.appendChild(row)
+    }
+  }
+
+  const open = (): void => {
+    render()
+    overlay.style.display = 'flex'
+    timer = setInterval(render, 1000)
+  }
+  const hide = (): void => {
+    overlay.style.display = 'none'
+    if (timer !== null) {
+      clearInterval(timer)
+      timer = null
+    }
+  }
+  overlay.addEventListener('click', (e) => {
+    if (e.target === overlay) hide()
+  })
+
+  const btn = document.createElement('button')
+  btn.className = 'toolbtn'
+  btn.textContent = '▦'
+  btn.title = 'All sessions'
+  btn.setAttribute('aria-label', 'All sessions')
+  btn.addEventListener('click', () => (overlay.style.display === 'none' ? open() : hide()))
+  toolbar.appendChild(btn)
+}