feat: 영수증 스캔 네이티브 카메라(@capacitor/camera)

- 앱에서 촬영/갤러리 선택 프롬프트로 영수증 입력 (웹은 파일선택 폴백)
- AndroidManifest CAMERA 권한 추가

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

android/capacitor.settings.gradle

@@ -5,5 +5,8 @@ project(':capacitor-android').projectDir = new File('../node_modules/@capacitor/
 include ':capacitor-app'
 project(':capacitor-app').projectDir = new File('../node_modules/@capacitor/app/android')
 
+include ':capacitor-camera'
+project(':capacitor-camera').projectDir = new File('../node_modules/@capacitor/camera/android')
+
 include ':capacitor-preferences'
 project(':capacitor-preferences').projectDir = new File('../node_modules/@capacitor/preferences/android')