test(mobile): integration suite against real backend on mumu

P3 Task 11 (WRITE & COMPILE phase; device run pending MuMu availability).

- integration_test/p3_flow_test.dart: login -> album (zh+en) -> category
  -> invite -> enqueue 3 real JPEGs -> queue completed -> server history
  (sourceDeviceId) -> ov public API sees 3 -> hide via API + UI sync ->
  DIO fault-gate offline (waitingNetwork -> retry -> 4 completed) ->
  password change (session kept) -> relogin -> in-app locale smoke.
- integration_test/p3_background_test.dart: IT_PHASE=prepare/verify spec
  for HOME-background continuation and force-stop kill-restart recovery
  (2 x ~14MB noise JPEGs give a deterministic mid-flight window).
- helpers: dart-define config, fault-injecting DIO adapter, app harness
  (picker/notification/locale provider overrides), UI step library with
  live-binding polling (no pumpAndSettle).
- scripts/run-mobile-it.sh: device detect (exit 2), backend ensure
  (compose + api/ov/worker/sync, exit 3), idempotent per-run user seed
  (no DB reset), APK build/install + adb push of testdata, phase 1 /
  --background phase 2 orchestration with server-side confirmed-count
  truth via curl.
- services/api seed:it script (create-if-absent staff accounts).
- debug-only network security config: cleartext HTTP permitted to
  10.0.2.2/127.0.0.1/localhost only (release unaffected).
- testdata: 3 x ~120KB + 2 x ~14MB generated JPEGs.

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

apps/mobile/pubspec.lock

@@ -326,6 +326,11 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_driver:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   flutter_lints:
     dependency: "direct dev"
     description:
@@ -413,6 +418,11 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  fuchsia_remote_debug_protocol:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   glob:
     dependency: transitive
     description:
@@ -525,6 +535,11 @@ packages:
       url: "https://pub.flutter-io.cn"
     source: hosted
     version: "0.2.2"
+  integration_test:
+    dependency: "direct dev"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   intl:
     dependency: "direct main"
     description:
@@ -757,6 +772,14 @@ packages:
       url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.5.3"
+  process:
+    dependency: transitive
+    description:
+      name: process
+      sha256: "4242ba3508d37e01808bdf71ad1d5bb93a8d671bf2e7450e6b1b353fb0808891"
+      url: "https://pub.flutter-io.cn"
+    source: hosted
+    version: "5.0.6"
   pub_semver:
     dependency: transitive
     description:
@@ -970,6 +993,14 @@ packages:
       url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.4.1"
+  sync_http:
+    dependency: transitive
+    description:
+      name: sync_http
+      sha256: "7f0cd72eca000d2e026bcd6f990b81d0ca06022ef4e32fb257b30d3d1014a961"
+      url: "https://pub.flutter-io.cn"
+    source: hosted
+    version: "0.3.1"
   term_glyph:
     dependency: transitive
     description:
@@ -1058,6 +1089,14 @@ packages:
       url: "https://pub.flutter-io.cn"
     source: hosted
     version: "3.0.3"
+  webdriver:
+    dependency: transitive
+    description:
+      name: webdriver
+      sha256: "28b82ec894fed45dd71c23ba62d1af973ed97dd59a4f5790a4d38b0b13e5657e"
+      url: "https://pub.flutter-io.cn"
+    source: hosted
+    version: "3.2.0"
   win32:
     dependency: transitive
     description: