Fix event manager race conditions and test teardown after mocha-to-vitest migration

[Copilot]

After switching from mocha to vitest, tests failed intermittently due to vitest's different isolation/parallelism defaults exposing pre-existing race conditions in the Firebird event system that mocha's sequential single-process execution masked.

Event manager race conditions (lib/wire/fbEventManager.js)

The event loop's eventcallback can fire between any two operations on the main connection, pushing a spurious queEvents callback onto the queue. This misaligns the callback queue so subsequent operations consume the wrong response and hang.

• close(): Null out eventcallback before closeEvents to prevent re-queuing from stale op_event notifications
• _changeEvent(): Same fix — suppress eventcallback during closeEvents + queEvents, restore after completion
• close() callback: Was never invoked on success, causing await-style callers to hang forever

// Before: stale op_event fires loop() between closeEvents and queEvents
_changeEvent(callback) {
    self.db.connection.closeEvents(this.eventid, function (err) {
        self.db.connection.queEvents(self.events, self.eventid, callback);
    })
}

// After: suppress event loop during the critical section
_changeEvent(callback) {
    var savedCallback = self.eventconnection.eventcallback;
    self.eventconnection.eventcallback = null;
    self.db.connection.closeEvents(this.eventid, function (err) {
        self.db.connection.queEvents(self.events, self.eventid, function (err, ret) {
            self.eventconnection.eventcallback = savedCallback;
            callback(err, ret);
        });
    })
}

Test fixes

• test/index.js: Close event managers after each test; resilient afterAll with timeout + force socket close; fix Object.assign(config) → Object.assign({}, config) no-op
• test/service.js: Drain readable streams returned by service property setters before calling getStats — undrained streams hold Firebird server locks, causing "Lock time-out" on setReadonlyMode/setReadwriteMode

Vitest configuration (vitest.config.js)

• isolate: false, fileParallelism: false, maxWorkers: 1 — match mocha's single-process sequential execution model
• hookTimeout: 30000 — database creation hooks need headroom on CI
• Ordered include list: service.js before index.js since service tests need exclusive DB access

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.