v2.0.0: BooCoder frontend — chat pane + diff pane + session picker

Integrates BooCoder as a 'coder' workspace pane within the existing
BooChat SPA at code.indifferentketchup.com. Renamed the placeholder
'agent' pane kind to 'coder' across all types, menus, hooks, and
mobile switcher (Icon: Code instead of Bot).

CoderPane.tsx: split layout with chat area (messages via WS to
boocoder:9502, input bar posting to /api/coder/sessions/:id/messages)
and diff panel (pending changes with Approve/Reject per change plus
Approve All/Reject All). Reuses MarkdownRenderer for message content.

Proxy: Vite dev config adds /api/coder → boocoder:9502 (ordered above
/api per CLAUDE.md proxy-ordering rule). Production: Fastify route in
apps/server/src/index.ts proxies /api/coder/* to http://boocoder:3000
via fetch() pass-through. WS connects directly to :9502 (same
Tailscale network, no proxy needed for WebSocket upgrade).

WorkspacePaneKind mirror updated in both apps/web and apps/server
types. useWorkspacePanes gains coderPane() factory (replaces the old
agent toast stub). Workspace.tsx switch renders CoderPane for
pane.kind === 'coder'.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/vite.config.ts

@@ -30,6 +30,17 @@ export default defineConfig({
           'Remote-User': process.env.DEV_REMOTE_USER ?? 'sam',
         },
       },
+      // BooCoder: proxy /api/coder/* to the coder container. Must be listed
+      // before /api so the more-specific prefix matches first.
+      '/api/coder': {
+        target: process.env.BOOCODER_DEV_URL ?? 'http://127.0.0.1:9502',
+        changeOrigin: true,
+        ws: true,
+        rewrite: (path: string) => path.replace(/^\/api\/coder/, '/api'),
+        headers: {
+          'Remote-User': process.env.DEV_REMOTE_USER ?? 'sam',
+        },
+      },
       '/api': {
         target: 'http://127.0.0.1:3000',
         changeOrigin: true,