fix(mobile): route phone APIs to selected profile and unblock runtime readiness

apps/desktop/electron/primary-backend-startup.test.ts

@@ -173,3 +173,21 @@ test('reset rejects with a typed error and never enters either backend', async (
   assert.equal(options.connectRemote.mock.calls.length, 0)
   assert.equal(options.ensureLocalRuntime.mock.calls.length, 0)
 })
+
+test('a sibling runtime completion re-resolves the primary profile without re-running the stale installer', async () => {
+  const gate = createFirstRunSetupGate({ stuckAfterMs: 0 })
+  const installed = { kind: 'python', activeRoot: bootstrapBackend.activeRoot, args: ['--profile', 'fusion-frontier'] }
+  const prepareLocalBackend = vi.fn().mockResolvedValueOnce(bootstrapBackend).mockResolvedValue(installed)
+  const options = startupOptions({ waitForDecision: gate.wait, prepareLocalBackend })
+  const pending = runPrimaryBackendStartup(options)
+  await vi.waitFor(() => assert.equal(gate.hasWaiter(), true))
+  gate.runtimeAvailable(bootstrapBackend.activeRoot)
+  await pending
+  assert.deepEqual(options.ensureLocalRuntime.mock.calls, [[installed]])
+})
+
+test('a runtime that disappeared after readiness cannot silently trigger another installation', async () => {
+  const options = startupOptions({ waitForDecision: async () => 'runtime-ready' as const })
+  await assert.rejects(runPrimaryBackendStartup(options), /no longer available/)
+  assert.equal(options.ensureLocalRuntime.mock.calls.length, 0)
+})