feat(unionflow): ajout Spec-Kit, constitution, mission mutuelles

- Config Spec-Kit pour Spec-Driven Development
- CONSTITUTION.md + .specify/memory/constitution.md
- Commandes Cursor /speckit.*, règles projet
- Mission: associations + mutuelles d'épargne et de financement
- .gitignore: versionner config spec-kit unionflow

Made-with: Cursor

unionflow/unionflow-mobile-apps/android/app/proguard-rules.pro

@@ -0,0 +1,17 @@
+# Flutter ProGuard Rules
+-keep class io.flutter.** { *; }
+-keep class io.flutter.plugins.** { *; }
+-dontwarn io.flutter.embedding.**
+
+# Keep annotations
+-keepattributes *Annotation*
+
+# Keep Keycloak/OAuth related classes
+-keep class net.openid.appauth.** { *; }
+
+# Keep Gson/JSON serialization
+-keepattributes Signature
+-keepattributes EnclosingMethod
+
+# Keep crypto classes for PKCE
+-keep class javax.crypto.** { *; }