feat: unify /me endpoint to aggregate all module profiles

GET /v1/iam/users/me now returns hackathon, QR, and mentor profiles
alongside the core IAM user data. Module-specific profiles are
included as optional fields when the user exists in those modules.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

imphnen-iam/Cargo.toml

@@ -23,6 +23,7 @@ zod-rs.workspace = true
 zod-rs-util.workspace = true
 axum-test.workspace = true
 sea-orm.workspace = true
+sqlx.workspace = true
 rand.workspace = true
 tokio.workspace = true
 chrono.workspace = true