feat(mobile): Implement Keycloak WebView authentication with HTTP callback

- Replace flutter_appauth with custom WebView implementation to resolve deep link issues
- Add KeycloakWebViewAuthService with integrated WebView for seamless authentication
- Configure Android manifest for HTTP cleartext traffic support
- Add network security config for development environment (192.168.1.11)
- Update Keycloak client to use HTTP callback endpoint (http://192.168.1.11:8080/auth/callback)
- Remove obsolete keycloak_auth_service.dart and temporary scripts
- Clean up dependencies and regenerate injection configuration
- Tested successfully on multiple Android devices (Xiaomi 2201116TG, SM A725F)

BREAKING CHANGE: Authentication flow now uses WebView instead of external browser
- Users will see Keycloak login page within the app instead of browser redirect
- Resolves ERR_CLEARTEXT_NOT_PERMITTED and deep link state management issues
- Maintains full OIDC compliance with PKCE flow and secure token storage

Technical improvements:
- WebView with custom navigation delegate for callback handling
- Automatic token extraction and user info parsing from JWT
- Proper error handling and user feedback
- Consistent authentication state management across app lifecycle

update-redirect-uri.ps1

@@ -0,0 +1,41 @@
+# Script pour ajouter la nouvelle redirect URI
+$KeycloakUrl = "http://192.168.1.11:8180"
+$Realm = "unionflow"
+$ClientId = "unionflow-mobile"
+
+Write-Host "=== AJOUT NOUVELLE REDIRECT URI ===" -ForegroundColor Cyan
+
+try {
+    # Obtenir token admin
+    $tokenBody = "username=admin&password=admin&grant_type=password&client_id=admin-cli"
+    $tokenResponse = Invoke-RestMethod -Uri "$KeycloakUrl/realms/master/protocol/openid-connect/token" -Method Post -ContentType "application/x-www-form-urlencoded" -Body $tokenBody
+    $accessToken = $tokenResponse.access_token
+    
+    # Récupérer le client
+    $headers = @{ "Authorization" = "Bearer $accessToken" }
+    $clients = Invoke-RestMethod -Uri "$KeycloakUrl/admin/realms/$Realm/clients?clientId=$ClientId" -Method Get -Headers $headers
+    $client = $clients[0]
+    $clientUuid = $client.id
+    
+    Write-Host "Client trouvé: $clientUuid" -ForegroundColor Green
+    
+    # Ajouter les nouvelles redirect URIs
+    $newRedirectUris = @(
+        "com.unionflow.mobile://login-callback",
+        "com.unionflow.mobile://oauth/callback"
+    )
+    
+    $client.redirectUris = $newRedirectUris
+    
+    # Convertir en JSON et mettre à jour
+    $clientJson = $client | ConvertTo-Json -Depth 10
+    Invoke-RestMethod -Uri "$KeycloakUrl/admin/realms/$Realm/clients/$clientUuid" -Method Put -Headers $headers -Body $clientJson -ContentType "application/json"
+    
+    Write-Host "✅ Redirect URIs mises à jour:" -ForegroundColor Green
+    foreach ($uri in $newRedirectUris) {
+        Write-Host "  - $uri" -ForegroundColor Gray
+    }
+    
+} catch {
+    Write-Host "Erreur: $($_.Exception.Message)" -ForegroundColor Red
+}