fix: v2.0.4+24 — login fixes, signup toggle, forgot-password, guest SnackBar, Google OAuth

- Google Sign-In: wire serverClientId (639347358523-mtkm...apps.googleusercontent.com) so idToken is returned on Android
- Email login: raise timeout 10s→25s, add single retry on SocketException/TimeoutException
- Forgot Password: real glassmorphism bottom sheet with safe-degrade SnackBar (endpoint missing on backend)
- Create Account: same-page AnimatedSwitcher toggle with glassmorphism signup form; delete old RegisterScreen
- Desktop parity: DesktopLoginScreen same-page toggle; delete DesktopRegisterScreen
- Guest mode: remove ScaffoldMessenger SnackBar from HomeScreen outer catch (inner _safe wrappers already return [])
- LoginScreen: clearSnackBars() on postFrameCallback to prevent carried-over SnackBars from prior screens
- ProGuard: add Google Sign-In + OkHttp keep rules
- Version bump: 2.0.0+20 → 2.0.4+24; settings _appVersion → 2.0.4

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

android/app/proguard-rules.pro

@@ -26,3 +26,62 @@
 -dontwarn com.google.android.play.core.tasks.OnFailureListener
 -dontwarn com.google.android.play.core.tasks.OnSuccessListener
 -dontwarn com.google.android.play.core.tasks.Task
+
+# Razorpay
+-keepattributes *Annotation*,Signature,*Annotation*
+-dontwarn com.razorpay.**
+-keep class com.razorpay.** { *; }
+-optimizations !method/inlining/
+-keepclasseswithmembers class * {
+  public void onPayment*(...);
+}
+-keep class proguard.annotation.Keep
+-keep class proguard.annotation.KeepClassMembers
+-keep @proguard.annotation.Keep class * { *; }
+-keep @proguard.annotation.KeepClassMembers class * {
+  <fields>;
+  <methods>;
+}
+
+# Google Sign-In / Play Services
+-keep class com.google.android.gms.** { *; }
+-keep interface com.google.android.gms.** { *; }
+-dontwarn com.google.android.gms.**
+-keep class com.google.firebase.** { *; }
+-dontwarn com.google.firebase.**
+
+# Geolocator / Geocoding
+-keep class com.baseflow.** { *; }
+-dontwarn com.baseflow.**
+
+# url_launcher, share_plus, image_picker, path_provider, etc.
+-keep class io.flutter.plugins.** { *; }
+-dontwarn io.flutter.plugins.**
+
+# OkHttp (used by many network libs)
+-dontwarn okhttp3.**
+-dontwarn okio.**
+-dontwarn javax.annotation.**
+-keep class okhttp3.** { *; }
+-keep interface okhttp3.** { *; }
+
+# Keep native methods
+-keepclasseswithmembernames class * {
+    native <methods>;
+}
+
+# Keep Parcelable classes
+-keep class * implements android.os.Parcelable {
+  public static final android.os.Parcelable$Creator *;
+}
+
+# Keep Serializable classes
+-keepclassmembers class * implements java.io.Serializable {
+    static final long serialVersionUID;
+    private static final java.io.ObjectStreamField[] serialPersistentFields;
+    !static !transient <fields>;
+    private void writeObject(java.io.ObjectOutputStream);
+    private void readObject(java.io.ObjectInputStream);
+    java.lang.Object writeReplace();
+    java.lang.Object readResolve();
+}