fix: 플로팅 네비게이션 바 렌더링 문제 해결

- SMS 화면에서 그림자가 제대로 표시되지 않던 문제 수정
- Stack 구조를 Container로 단순화하여 렌더링 최적화
- RenderFlex overflow 오류 해결 (패딩 및 아이콘 크기 조정)
- Android 패키지명 변경 및 빌드 설정 업데이트

pubspec.lock

@@ -50,10 +50,10 @@ packages:
     dependency: transitive
     description:
       name: async
-      sha256: d2872f9c19731c2e5f10444b14686eb7cc85c76274bd6c16e1816bff9a3bab63
+      sha256: "758e6d74e971c3e5aceb4110bfd6698efc7f501675bcfe0c775459a8140750eb"
       url: "https://pub.dev"
     source: hosted
-    version: "2.12.0"
+    version: "2.13.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -266,10 +266,10 @@ packages:
     dependency: transitive
     description:
       name: fake_async
-      sha256: "6a95e56b2449df2273fd8c45a662d6947ce1ebb7aafe80e550a3f68297f3cacc"
+      sha256: "5368f224a74523e8d2e7399ea1638b37aecfca824a3cc4dfdf77bf1fa905ac44"
       url: "https://pub.dev"
     source: hosted
-    version: "1.3.2"
+    version: "1.3.3"
   ffi:
     dependency: transitive
     description:
@@ -566,10 +566,10 @@ packages:
     dependency: "direct main"
     description:
       name: intl
-      sha256: d6f56758b7d3014a48af9701c085700aac781a92a87a62b1333b46d8879661cf
+      sha256: "3df61194eb431efc39c4ceba583b95633a403f46c9fd341e550ce0bfa50e9aa5"
       url: "https://pub.dev"
     source: hosted
-    version: "0.19.0"
+    version: "0.20.2"
   io:
     dependency: transitive
     description:
@@ -598,10 +598,10 @@ packages:
     dependency: transitive
     description:
       name: leak_tracker
-      sha256: c35baad643ba394b40aac41080300150a4f08fd0fd6a10378f8f7c6bc161acec
+      sha256: "6bb818ecbdffe216e81182c2f0714a2e62b593f4a4f13098713ff1685dfb6ab0"
       url: "https://pub.dev"
     source: hosted
-    version: "10.0.8"
+    version: "10.0.9"
   leak_tracker_flutter_testing:
     dependency: transitive
     description:
@@ -1299,10 +1299,10 @@ packages:
     dependency: transitive
     description:
       name: vm_service
-      sha256: "0968250880a6c5fe7edc067ed0a13d4bae1577fe2771dcf3010d52c4a9d3ca14"
+      sha256: ddfa8d30d89985b96407efce8acbdd124701f96741f2d981ca860662f1c0dc02
       url: "https://pub.dev"
     source: hosted
-    version: "14.3.1"
+    version: "15.0.0"
   watcher:
     dependency: transitive
     description: