chat: read the /chat session list from Claude's own transcript store

First slice of making Claude's session store the source of truth. Adds a reader
(api/chat/claude-sessions.ts) that lists sessions straight from Claude's JSONL
transcripts under $HOME/.claude/projects/<cwd-slug>/, plus GET /chat/sessions
over a dedicated per-user claude_sessions working directory. No bookkeeping
layer — Claude's files are authoritative. Verified against real transcripts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/hono.ts

@@ -31,6 +31,7 @@ import { desktopRouter } from './api/desktop/rest';
 import { appsRouter, appServeRouter } from './api/apps';
 import { bugReportRouter } from './api/bug-report/bug-report';
 import { savedSessionsRouter } from './api/saved-sessions/saved-sessions';
+import { chatRouter } from './api/chat/chat';
 import { pipelineJobsRouter } from './api/tasks/pipeline-jobs-routes';
 import { broadcastPanelRefresh } from './api/terminal/websocket';
 import { CustomError } from './custom-errors';
@@ -103,6 +104,7 @@ protectedRouter.route('/browser', browserRouter);
 protectedRouter.route('/apps', appsRouter);
 protectedRouter.route('/bug-report', bugReportRouter);
 protectedRouter.route('/saved-sessions', savedSessionsRouter);
+protectedRouter.route('/chat', chatRouter);
 protectedRouter.route('/pipeline-jobs', pipelineJobsRouter);
 protectedRouter.route('/jobs', pipelineJobsRouter); // unified jobs API (script + pipeline); /pipeline-jobs kept for the existing UI
 desktopRouter.use(superAdminMiddleware);