feat: add multi-environment support (development, staging, production)

- Replace dotenv with compile-time dart-define-from-file config per flavor
  - Add Android product flavors with applicationIdSuffix and per-flavor AndroidManifest
  - Add iOS build configurations, schemes, per-flavor plists and entitlements
  - Configure ProGuard rules for R8 compatibility with Entrust/Antelop SDK
  - Restructure assets into shared/ and per-flavor directories
  - Generate per-flavor launcher icons for Android and iOS
  - Refactor app initialization into initApp() with per-flavor entry points
  - Update asset paths across auth, home, profile, splash modules and sf_shared

.vscode/launch.json

@@ -5,14 +5,37 @@
     "version": "0.2.0",
     "configurations": [
         {
-            "name": "sf_app_platform",
+            "name": "SF Development",
             "cwd": "apps/mobile_app",
             "request": "launch",
             "type": "dart",
-            // "toolArgs": [
-            //     "--dart-define=ELEVENLABS_API_KEY=sk_2351c16102e66b5b5c26d022d73e8af203fda111f60516f6",
-            //     "--dart-define=ELEVENLABS_VOICE_ID=kaOF79CUr1VcYoAoVbqa"
-            // ]
+            "args": [
+                "--flavor",
+                "development",
+                "--dart-define-from-file=config/development.json"
+            ]
+        },
+        {
+            "name": "SF Staging",
+            "cwd": "apps/mobile_app",
+            "request": "launch",
+            "type": "dart",
+            "args": [
+                "--flavor",
+                "staging",
+                "--dart-define-from-file=config/staging.json"
+            ]
+        },
+        {
+            "name": "SF Production",
+            "cwd": "apps/mobile_app",
+            "request": "launch",
+            "type": "dart",
+            "args": [
+                "--flavor",
+                "production",
+                "--dart-define-from-file=config/production.json"
+            ]
         }
     ]
-}
+}