feat: add Koa2 BFF server, CLI management, sessions CLI integration, and logs page

- Add Koa2 BFF layer for API proxy, file upload, session management
- Auto-check and enable api_server in ~/.hermes/config.yaml on startup
- Integrate sessions with Hermes CLI (list, get, delete)
- Add Logs page with level filtering, log file selection, and search
- Add CLI commands: start/stop/restart/status for daemon management
- Unify package.json for frontend and server dependencies
- Default port changed to 8648

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

server/src/routes/sessions.ts

@@ -0,0 +1,34 @@
+import Router from '@koa/router'
+import * as hermesCli from '../services/hermes-cli'
+
+export const sessionRoutes = new Router()
+
+// List sessions from Hermes
+sessionRoutes.get('/api/sessions', async (ctx) => {
+  const source = (ctx.query.source as string) || undefined
+  const limit = ctx.query.limit ? parseInt(ctx.query.limit as string, 10) : undefined
+  const sessions = await hermesCli.listSessions(source, limit)
+  ctx.body = { sessions }
+})
+
+// Get single session with messages
+sessionRoutes.get('/api/sessions/:id', async (ctx) => {
+  const session = await hermesCli.getSession(ctx.params.id)
+  if (!session) {
+    ctx.status = 404
+    ctx.body = { error: 'Session not found' }
+    return
+  }
+  ctx.body = { session }
+})
+
+// Delete session from Hermes
+sessionRoutes.delete('/api/sessions/:id', async (ctx) => {
+  const ok = await hermesCli.deleteSession(ctx.params.id)
+  if (!ok) {
+    ctx.status = 500
+    ctx.body = { error: 'Failed to delete session' }
+    return
+  }
+  ctx.body = { ok: true }
+})