refactor(sync): collapse 11 sync args into forwarded token array

- Replace syncHost/syncSnapshotPath/… with syncCliTokens: string[] passed verbatim to --sync-cli sync
- Move sync CLI validation from launcher to parseSyncCliTokens (app-side single owner)
- Extract resolveImmersionDbPath to shared db-path.ts importable by both launcher and app
- Delete driver.ts; inline types into libsql-driver.ts and hard-wire openLibsqlSyncDb
- Drop OpenSyncDb injection from mergeSnapshotIntoDb and createDbSnapshot

launcher/mpv.test.ts

@@ -603,17 +603,7 @@ function makeArgs(overrides: Partial<Args> = {}): Args {
     useRofi: false,
     history: false,
     sync: false,
-    syncHost: '',
-    syncSnapshotPath: '',
-    syncMergePath: '',
-    syncDirection: 'both',
-    syncRemoteCmd: '',
-    syncDbPath: '',
-    syncForce: false,
-    syncJson: false,
-    syncCheck: false,
-    syncMakeTemp: false,
-    syncRemoveTempPath: '',
+    syncCliTokens: [],
     syncUi: false,
     logLevel: 'error',
     logRotation: 7,