fix: resolve test failures related to v0.5.12 changes (#491)

* fix: update tests for new batch delete and update mechanism changes

**sessions-routes.test.ts:**
- Add missing batchRemove mock to controller mock
- Fix "No batchRemove export defined" error

**update-controller.test.ts:**
- Update test to expect direct npm/npm.cmd calls instead of dirname(process.execPath)
- Update timeout from 120000 to 10 * 60 * 1000 (10 minutes)
- Update spawn path check to use dynamic global prefix (expect.any)

Tests now match the refactored update mechanism that uses npm prefix -g
for reliable path resolution.

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

* test: add speechSynthesis mock to message-item-highlight tests

* test: fix all failing tests

- Add approvals mock to session-settings test
- Fix NSwitch stub to properly emit events
- Update usage stats test expectations for new field structure
- Mock getDb in model-context tests to avoid database lock errors
- Add speechSynthesis API mock to message-item-highlight tests

Related to v0.5.12 feature changes

---------

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

tests/server/model-context.test.ts

@@ -25,6 +25,14 @@ async function loadModelContext() {
     ...(await vi.importActual<typeof import('os')>('os')),
     homedir: () => homeDir,
   }))
+  // Mock getDb to return null to avoid "database is locked" errors in parallel tests
+  vi.doMock('../../packages/server/src/db/index', async () => {
+    const actual = await vi.importActual<typeof import('../../packages/server/src/db/index')>('../../packages/server/src/db/index')
+    return {
+      ...actual,
+      getDb: () => null,
+    }
+  })
   return import('../../packages/server/src/services/hermes/model-context')
 }