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/terminal-session.ts

@@ -9,6 +9,7 @@
  */
 
 import { Terminal } from '@xterm/xterm'
+import type { ITheme } from '@xterm/xterm'
 import { FitAddon } from '@xterm/addon-fit'
 import { SearchAddon } from '@xterm/addon-search'
 import { WebLinksAddon } from '@xterm/addon-web-links'
@@ -302,6 +303,16 @@ export class TerminalSession {
     this.searchAddon.clearDecorations()
   }
 
+  /** Apply a theme + font size (M3) and re-fit if visible. */
+  applyTheme(theme: ITheme, fontSize: number): void {
+    this.term.options.theme = theme
+    this.term.options.fontSize = fontSize
+    if (this.el.style.display !== 'none') {
+      const dims = this.safefit()
+      if (dims !== null) this.sendResize(dims.cols, dims.rows)
+    }
+  }
+
   /** Make this pane visible, fit it, and focus it. */
   show(): void {
     this.el.style.display = 'block'