saved sessions: replace transient history with persistent DB storage and auto-save

- Add saved_sessions table and CRUD endpoints (save, list, resume, update, delete)
- Save is instant (no LLM summarization), stores exact conversation with tool calls
- Resume loads full message history into chat UI, sends transcript to agent on first message
- Auto-save updates DB after every agent response once a session is saved
- Delete old filesystem-based session/group management (sessions router, useChatSessions, useChatGroups)
- Clean up ChatHeader, SessionList, ChatDetailPanel for saved sessions flow

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/servers/hono.ts

@@ -12,7 +12,6 @@ import { skillsRouter } from './api/skills/skills';
 import { tasksRouter } from './api/tasks/tasks';
 import { toolsRouter } from './api/tools/tools';
 import { processesRouter } from './api/processes/processes';
-import { sessionsRouter } from './api/sessions/sessions';
 import { scrapeRouter } from './api/scrape/scrape';
 import { uploadRouter } from './api/upload/upload';
 import { settingsRouter } from './api/settings/settings';
@@ -30,6 +29,7 @@ import { browserRouter } from './api/browser/router';
 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 { broadcastPanelRefresh } from './api/terminal/websocket';
 import { CustomError } from './custom-errors';
 import { userMiddleware, bodyParser, isOriginAllowed, superAdminMiddleware } from './_middlewares';
@@ -84,7 +84,6 @@ protectedRouter.route('/skills', skillsRouter);
 protectedRouter.route('/tasks', tasksRouter);
 protectedRouter.route('/tools', toolsRouter);
 protectedRouter.route('/processes', processesRouter);
-protectedRouter.route('/', sessionsRouter);
 protectedRouter.route('/scrape', scrapeRouter);
 protectedRouter.route('/upload', uploadRouter);
 protectedRouter.route('/user', settingsRouter);
@@ -100,6 +99,7 @@ protectedRouter.route('/channels', channelsRouter);
 protectedRouter.route('/browser', browserRouter);
 protectedRouter.route('/apps', appsRouter);
 protectedRouter.route('/bug-report', bugReportRouter);
+protectedRouter.route('/saved-sessions', savedSessionsRouter);
 desktopRouter.use(superAdminMiddleware);
 protectedRouter.route('/desktop', desktopRouter);
 protectedRouter.route('/', piRestRouter);