docs(sync): remote machine only needs the app - checklist, docs, changelog

Sync window drops the launcher-missing warning (self-spawn always works),
the setup checklist explains automatic remote discovery (SubMiner on
PATH, macOS /Applications, or the optional launcher), and the remote
resolver gains tests for app-binary fallback and --remote-cmd probing.

src/main/runtime/sync-ui-runtime.ts

@@ -123,14 +123,12 @@ export function createSyncUiRuntime(deps: SyncUiRuntimeDeps) {
   }
 
   function getSnapshot(): SyncUiSnapshot {
-    const resolution = deps.resolveLauncherCommand();
     return {
       dbPath: deps.getDbPath(),
       hosts: readState(),
       snapshotsDir: deps.snapshotsDir,
       snapshots: listSnapshots(),
       run: runState(),
-      launcherPath: resolution.command ? resolution.command.join(' ') : null,
     };
   }