refactor(db): unify SQLite table schema management and initialization (#310)

Centralized all 11 Hermes SQLite table definitions and initialization logic
into a single schemas.ts file to eliminate duplication and improve maintainability.

Changes:
- **NEW**: packages/server/src/db/hermes/schemas.ts
  - Centralized schema definitions for all 11 tables
  - Unified initAllHermesTables() function with migration logic
  - Includes usage table PRIMARY KEY migration (session_id → id)

- **Refactored**: packages/server/src/db/hermes/init.ts
  - Simplified from async to sync (all operations are synchronous)
  - Single responsibility: delegate to schemas.ts

- **Refactored**: packages/server/src/db/hermes/session-store.ts
  - Removed schema definitions (now in schemas.ts)
  - Removed initSessionStore() function
  - Imports table constants from schemas.ts

- **Refactored**: packages/server/src/db/hermes/usage-store.ts
  - Removed initUsageStore() function and migration logic
  - Migration moved to schemas.ts for consistency
  - Only handles CRUD operations now

- **Refactored**: packages/server/src/db/hermes/compression-snapshot.ts
  - Removed initCompressionSnapshotStore() function
  - Fixed duplicate getCompressionSnapshot definition
  - Imports table constant from schemas.ts

- **Refactored**: packages/server/src/services/hermes/group-chat/index.ts
  - Removed ensureTable() calls (now in schemas.ts)
  - Only handles index creation now
  - Imports table constants from schemas.ts

- **Updated**: packages/server/src/index.ts
  - Removed await from initAllStores() call (now sync)

Benefits:
- 🎯 Single responsibility: schemas.ts manages all tables, stores only do CRUD
- 📋 Centralized maintenance: all table definitions in one place
- 🔄 No duplication: each table created exactly once with proper migrations
- 🚀 Clean architecture: clear separation between initialization and operations

Tables managed (11 total):
1. session_usage (usage statistics)
2. sessions (session metadata)
3. messages (message content)
4. chat_compression_snapshots (compression snapshots)
5. gc_rooms (group chat rooms)
6. gc_messages (group chat messages)
7. gc_room_agents (room agents)
8. gc_context_snapshots (group chat snapshots)
9. gc_room_members (room members)
10. gc_pending_session_deletes (pending session deletes)
11. gc_session_profiles (session profiles)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/server/src/services/hermes/group-chat/index.ts

@@ -2,7 +2,8 @@ import { Server, Socket, Namespace } from 'socket.io'
 import type { Server as HttpServer } from 'http'
 import { getToken } from '../../../services/auth'
 import { logger } from '../../../services/logger'
-import { getDb, ensureTable } from '../../../db'
+import { getDb } from '../../../db'
+import { GC_ROOMS_TABLE, GC_MESSAGES_TABLE, GC_ROOM_AGENTS_TABLE, GC_CONTEXT_SNAPSHOTS_TABLE, GC_ROOM_MEMBERS_TABLE, GC_PENDING_SESSION_DELETES_TABLE, GC_SESSION_PROFILES_TABLE } from '../../../db/hermes/schemas'
 import { AgentClients } from './agent-clients'
 import { ContextEngine } from '../context-engine/compressor'
 import { SessionDeleter } from '../session-deleter'
@@ -139,14 +140,8 @@ class ChatStorage {
         if (_tablesEnsured) return
         const db = this.db()
         if (!db) return
-        ensureTable('gc_rooms', GC_ROOMS_SCHEMA)
-        ensureTable('gc_messages', GC_MESSAGES_SCHEMA)
-        ensureTable('gc_room_agents', GC_ROOM_AGENTS_SCHEMA)
-        ensureTable('gc_context_snapshots', GC_CONTEXT_SNAPSHOTS_SCHEMA)
-        ensureTable('gc_room_members', GC_ROOM_MEMBERS_SCHEMA)
-        ensureTable('gc_pending_session_deletes', GC_PENDING_SESSION_DELETES_SCHEMA)
-        ensureTable('gc_session_profiles', GC_SESSION_PROFILES_SCHEMA)
-        // Indexes (safe to run multiple times — CREATE INDEX IF NOT EXISTS)
+        // Tables are now created centrally in initAllHermesTables()
+        // Only create indexes here
         try { db.exec('CREATE INDEX IF NOT EXISTS idx_gc_messages_room ON gc_messages(roomId, timestamp)') } catch { /* ignore */ }
         try { db.exec('CREATE INDEX IF NOT EXISTS idx_gc_room_agents_room ON gc_room_agents(roomId)') } catch { /* ignore */ }
         try { db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_gc_room_members_unique ON gc_room_members(roomId, userId)') } catch { /* ignore */ }