feat(v2): add SSH management, ctx integration, themes, detached mode, auto-updater

SSH session management:
- SshSession struct + ssh_sessions SQLite table in session.rs
- CRUD Tauri commands (ssh_session_list/save/delete) in lib.rs
- SshDialog.svelte (create/edit modal), SshSessionList.svelte (sidebar)
- SSH pane routes to TerminalPane with shell=/usr/bin/ssh + args

ctx context database integration:
- ctx.rs: read-only CtxDb (SQLITE_OPEN_READ_ONLY for ~/.claude-context/context.db)
- 5 Tauri commands (ctx_list_projects/get_context/get_shared/get_summaries/search)
- ContextPane.svelte with project selector, tabs, search
- ctx-bridge.ts adapter

Catppuccin theme flavors (Latte/Frappe/Macchiato/Mocha):
- themes.ts: all 4 palette definitions + buildXtermTheme/applyCssVariables
- theme.svelte.ts: reactive store with SQLite persistence
- SettingsDialog flavor dropdown, TerminalPane theme-aware

Detached pane mode (pop-out windows):
- detach.ts: isDetachedMode/getDetachedConfig from URL params
- App.svelte: conditional rendering of single pane without chrome

Other additions:
- Shiki syntax highlighting (highlight.ts, lazy singleton, 13 languages)
- Tauri auto-updater plugin (tauri-plugin-updater + updater.ts)
- AgentPane markdown rendering with Shiki code highlighting
- New deps: shiki, @tauri-apps/plugin-updater, tauri-plugin-updater

v2/src/lib/utils/detach.ts

@@ -0,0 +1,68 @@
+// Detachable pane support — opens panes in separate OS windows
+// Uses Tauri's WebviewWindow API
+
+import { WebviewWindow } from '@tauri-apps/api/webviewWindow';
+import type { Pane } from '../stores/layout.svelte';
+
+let detachCounter = 0;
+
+export async function detachPane(pane: Pane): Promise<void> {
+  detachCounter++;
+  const label = `detached-${detachCounter}`;
+
+  const params = new URLSearchParams({
+    detached: 'true',
+    type: pane.type,
+    title: pane.title,
+  });
+
+  if (pane.shell) params.set('shell', pane.shell);
+  if (pane.cwd) params.set('cwd', pane.cwd);
+  if (pane.args) params.set('args', JSON.stringify(pane.args));
+  if (pane.type === 'agent') params.set('sessionId', pane.id);
+
+  const webview = new WebviewWindow(label, {
+    url: `index.html?${params.toString()}`,
+    title: `BTerminal — ${pane.title}`,
+    width: 800,
+    height: 600,
+    decorations: true,
+    resizable: true,
+  });
+
+  // Wait for the window to be created
+  await webview.once('tauri://created', () => {
+    // Window created successfully
+  });
+
+  await webview.once('tauri://error', (e) => {
+    console.error('Failed to create detached window:', e);
+  });
+}
+
+export function isDetachedMode(): boolean {
+  const params = new URLSearchParams(window.location.search);
+  return params.get('detached') === 'true';
+}
+
+export function getDetachedConfig(): {
+  type: string;
+  title: string;
+  shell?: string;
+  cwd?: string;
+  args?: string[];
+  sessionId?: string;
+} | null {
+  const params = new URLSearchParams(window.location.search);
+  if (params.get('detached') !== 'true') return null;
+
+  const argsStr = params.get('args');
+  return {
+    type: params.get('type') ?? 'terminal',
+    title: params.get('title') ?? 'Detached',
+    shell: params.get('shell') ?? undefined,
+    cwd: params.get('cwd') ?? undefined,
+    args: argsStr ? JSON.parse(argsStr) : undefined,
+    sessionId: params.get('sessionId') ?? undefined,
+  };
+}

v2/src/lib/utils/highlight.ts

@@ -0,0 +1,51 @@
+import { createHighlighter, type Highlighter } from 'shiki';
+
+let highlighter: Highlighter | null = null;
+let initPromise: Promise<Highlighter> | null = null;
+
+// Use catppuccin-mocha theme (bundled with shiki)
+const THEME = 'catppuccin-mocha';
+
+// Common languages to preload
+const LANGS = [
+  'typescript', 'javascript', 'rust', 'python', 'bash',
+  'json', 'html', 'css', 'svelte', 'sql', 'yaml', 'toml', 'markdown',
+];
+
+export async function getHighlighter(): Promise<Highlighter> {
+  if (highlighter) return highlighter;
+  if (initPromise) return initPromise;
+
+  initPromise = createHighlighter({
+    themes: [THEME],
+    langs: LANGS,
+  });
+
+  highlighter = await initPromise;
+  return highlighter;
+}
+
+export function highlightCode(code: string, lang: string): string {
+  if (!highlighter) return escapeHtml(code);
+
+  try {
+    const loadedLangs = highlighter.getLoadedLanguages();
+    if (!loadedLangs.includes(lang as any)) {
+      return escapeHtml(code);
+    }
+
+    return highlighter.codeToHtml(code, {
+      lang,
+      theme: THEME,
+    });
+  } catch {
+    return escapeHtml(code);
+  }
+}
+
+export function escapeHtml(text: string): string {
+  return text
+    .replace(/&/g, '&amp;')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;');
+}

v2/src/lib/utils/updater.ts

@@ -0,0 +1,32 @@
+// Auto-update checker — uses Tauri updater plugin
+// Requires signing key to be configured in tauri.conf.json before use
+
+import { check } from '@tauri-apps/plugin-updater';
+
+export async function checkForUpdates(): Promise<{
+  available: boolean;
+  version?: string;
+  notes?: string;
+}> {
+  try {
+    const update = await check();
+    if (update) {
+      return {
+        available: true,
+        version: update.version,
+        notes: update.body ?? undefined,
+      };
+    }
+    return { available: false };
+  } catch {
+    // Updater not configured or network error — silently skip
+    return { available: false };
+  }
+}
+
+export async function installUpdate(): Promise<void> {
+  const update = await check();
+  if (update) {
+    await update.downloadAndInstall();
+  }
+}