feat(auth): Enhance Google OAuth service with CSRF protection and validation logic

feat(auth): Add error handling for authentication and validation errors
feat(auth): Implement default role assignment for new users in Google OAuth flow
feat(utils): Introduce CSRF token generation and validation utilities
fix(dependencies): Update Cargo.toml to include base64 and sha2 dependencies

Cargo.lock

@@ -2286,6 +2286,7 @@ dependencies = [
  "anyhow",
  "axum",
  "axum-test",
+ "base64 0.22.1",
  "chrono",
  "dotenvy",
  "imphnen-entities",
@@ -2293,6 +2294,7 @@ dependencies = [
  "rand 0.9.1",
  "serde",
  "serde_json",
+ "sha2",
  "strum 0.27.1",
  "strum_macros 0.27.1",
  "surrealdb",