test(int): drop redundant forceExit — bounded teardown already un-hangs test:int (#382)

The int suite could not self-exit after the ESM fix (8e125799) unmasked 4
specs, and was patched with two things: forceExit:true AND a bounded
destroyTestDb (sql.end({ timeout: 5 })). The bounded teardown is the real
fix — postgres.js .end() without a timeout blocks indefinitely on a stuck
pooled connection (the CI-observed "Jest did not exit"); the { timeout: 5 }
grace drains then force-closes sockets so teardown always completes.

forceExit was redundant belt-and-suspenders that also HID whether the
process truly exits on its own. Removing it: every handle-creating spec is
verified to close its handle — ai-chat-stream closes its http.createServer
in a finally, public-share-workspace-limiter closes its ioredis via
redis.quit() in afterAll, and the shared DB pools close via the bounded
destroyTestDb. --detectOpenHandles is clean and the suite self-exits.

Kept: the bounded destroyTestDb (defense for a genuinely stuck connection).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/server/test/jest-integration.json

@@ -16,7 +16,6 @@
   "testEnvironment": "node",
   "testTimeout": 60000,
   "maxWorkers": 1,
-  "forceExit": true,
   "globalSetup": "<rootDir>/test/integration/global-setup.ts",
   "globalTeardown": "<rootDir>/test/integration/global-teardown.ts",
   "moduleNameMapper": {