feat(api): add terminal session persistence with Prisma model and CRUD service

Adds database-backed TerminalSession model with ACTIVE/CLOSED status enum,
migration SQL, TerminalSessionService (create/findByWorkspace/close/findById),
DTO file with class-validator decorators, unit tests (12 tests), and module
registration. Workspace relation and indexed columns enable efficient session
listing and recovery.

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

apps/api/src/terminal/terminal.module.ts

@@ -5,10 +5,11 @@
  *
  * Imports:
  * - AuthModule for WebSocket authentication (verifySession)
- * - PrismaModule for workspace membership queries
+ * - PrismaModule for workspace membership queries and session persistence
  *
  * Providers:
- * - TerminalService: manages PTY session lifecycle
+ * - TerminalService: manages PTY session lifecycle (in-memory)
+ * - TerminalSessionService: persists session records to the database
  * - TerminalGateway: WebSocket gateway on /terminal namespace
  *
  * The module does not export providers; terminal sessions are
@@ -18,11 +19,13 @@
 import { Module } from "@nestjs/common";
 import { TerminalGateway } from "./terminal.gateway";
 import { TerminalService } from "./terminal.service";
+import { TerminalSessionService } from "./terminal-session.service";
 import { AuthModule } from "../auth/auth.module";
 import { PrismaModule } from "../prisma/prisma.module";
 
 @Module({
   imports: [AuthModule, PrismaModule],
-  providers: [TerminalGateway, TerminalService],
+  providers: [TerminalGateway, TerminalService, TerminalSessionService],
+  exports: [TerminalSessionService],
 })
 export class TerminalModule {}