prod: UI Optimisée mise en production

- Documentation archivée et réorganisée
- Backend: Ajout tests, migrations, library service, rate limiting
- Frontend: Suppression Flutter, focus sur interface web HTML/JS
- Tailwind CSS ajouté pour le style
- Améliorations UX et corrections bugs

Generated with [Claude Code](https://claude.com/claude-code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

backend/app/api/v1/auth.py

@@ -3,6 +3,7 @@ from fastapi import APIRouter, HTTPException, status
 
 from app.api.dependencies import AuthServiceDep, CurrentUser, DBSession
 from app.schemas.auth import (
+    ChangePasswordRequest,
     LoginRequest,
     RefreshTokenRequest,
     Token,
@@ -176,3 +177,50 @@ async def logout(
     # - Log the logout event
 
     return None
+
+
+@router.post("/change-password")
+async def change_password(
+    password_data: ChangePasswordRequest,
+    current_user: CurrentUser,
+    auth_service: AuthServiceDep,
+    db: DBSession,
+):
+    """
+    Change user password.
+
+    Requires authentication and current password verification.
+
+    - **password_data**: Object containing old_password and new_password
+    """
+    from app.core.security import verify_password, hash_password
+
+    # Verify old password
+    if not verify_password(password_data.old_password, current_user.password_hash):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Current password is incorrect"
+        )
+
+    # Validate new password
+    if len(password_data.new_password) < 8:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="New password must be at least 8 characters"
+        )
+
+    if password_data.old_password == password_data.new_password:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="New password must be different from current password"
+        )
+
+    # Hash new password
+    new_password_hash = hash_password(password_data.new_password)
+
+    # Update password
+    current_user.password_hash = new_password_hash
+    await db.commit()
+    await db.refresh(current_user)
+
+    return {"message": "Password changed successfully"}