fix: use dynamic import for node:sqlite with Node version guard

Replace static top-level import with runtime version check and dynamic
import() so Node < 22.5 gracefully falls back to CLI path instead of
crashing at module load time.

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

tests/server/sessions-db.test.ts

@@ -6,7 +6,7 @@ const closeMock = vi.fn()
 const databaseSyncMock = vi.fn(() => ({ prepare: prepareMock, close: closeMock }))
 const getActiveProfileDirMock = vi.fn(() => '/tmp/hermes-profile')
 
-vi.mock('node:sqlite', () => ({
+vi.doMock('node:sqlite', () => ({
   DatabaseSync: databaseSyncMock,
 }))