feat: spin-mobile — Flutter WebView 셸 (Android·iOS)

prod 웹앱(spin.special-partners.com)을 감싸는 네이티브 셸. 화면 개발 없음.
- InAppWebView: 쿠키/캐시 영속·UA(spinApp) 태그·풀투리프레시·외부링크 분기·오프라인 화면
- Android 하드웨어 뒤로가기(웹 히스토리→더블탭 종료), navy 스플래시/상태바
- 파일/카메라 업로드 권한(Android/iOS), 생체인증 잠금(local_auth)
- FCM 푸시(firebase_messaging) — 설정 전 자동 비활성, 토큰은 웹 세션으로 /api/devices 등록
- prod URL 고정(app_config.dart)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "self:">
+   </FileRef>
+</Workspace>

ios/Runner.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

ios/Runner.xcodeproj/project.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>PreviewsEnabled</key>
+	<false/>
+</dict>
+</plist>