refactor: centralize auth system across all modules

All modules now use the main IAM JWT (ACCESS_TOKEN_SECRET) for authentication,
removing three separate auth systems (hackathon Supabase, hackathon JWT, QR JWT).

Changes:
- hackathon: replace HackathonJwtService with decode_access_token() from imphnen-libs
  - remove entire src/auth/ (Supabase signup/login/GitHub/forgot-reset)
  - remove common/hackathon_jwt.rs, common/supabase_client.rs
  - remove Supabase from HackathonConfig (JWT, GitHub OAuth, Supabase anon/service keys)
  - replace Supabase Storage with MinioService from imphnen-libs
  - all route jwt params removed; hackathon_router takes MinioService instead
- qr: replace QrJwtService with decode_access_token() from imphnen-libs
  - remove entire src/auth/ (register/login/Google OAuth/refresh)
  - remove common/qr_jwt.rs, src/config.rs
  - qr_auth_middleware now lazy-upserts users into QR DB on first access
  - qr_router(pool) — no config needed
- gateway: create MinioService once and pass to hackathon_router; qr_router simplified

Users now register/login via /v1/auth/* and use the same JWT for all endpoints.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

imphnen-hackathon/src/invitations/infrastructure/http/routes.rs

@@ -4,11 +4,10 @@ use std::sync::Arc;
 use crate::invitations::application::invitation_service::InvitationServiceImpl;
 use crate::invitations::domain::service::InvitationService;
 use crate::invitations::infrastructure::persistence::PostgresInvitationRepository;
-use crate::common::hackathon_jwt::HackathonJwtService;
 use crate::middleware::hackathon_auth::hackathon_auth_middleware;
 use super::handlers::*;
 
-pub fn build_invitation_routes(pool: Arc<PgPool>, jwt: Arc<HackathonJwtService>) -> Router {
+pub fn build_invitation_routes(pool: Arc<PgPool>) -> Router {
     let service: Arc<dyn InvitationService> = Arc::new(InvitationServiceImpl::new(
         Arc::new(PostgresInvitationRepository::new(pool.clone())),
     ));
@@ -17,7 +16,6 @@ pub fn build_invitation_routes(pool: Arc<PgPool>, jwt: Arc<HackathonJwtService>)
         .route("/invitations/:invitation_id/respond", post(respond_to_invitation_handler))
         .route("/invitations/teams/:team_id/invite", post(invite_team_member_handler))
         .layer(Extension(service))
-        .layer(Extension(jwt.clone()))
         .layer(Extension(pool))
         .layer(from_fn(hackathon_auth_middleware))
 }