feat: v0.3.0 — standardize codebase, centralize infra, merge QR into CMS

- Enforce axum best practices across all 13 workspace crates
  (max 200 LOC/file, no comments, no unwrap, clean architecture)
- Fix domain→infrastructure dependency inversions in imphnen-iam and imphnen-dimentorin
- Extract imphnen-storage (MinIO) and imphnen-email (Lettre) as standalone crates
- Centralize all config in ENV struct: CDN_URL, CORS_ALLOWED_ORIGINS
- Centralize SMTP through imphnen-email; remove dead HackathonConfig
- Centralize database: QR crate now shares main DB pool (single DATABASE_URL)
- Rename QR users table to qr_users to avoid collision with main users table
- Merge imphnen-qr into imphnen-cms/src/qr (13 crates, down from 14)
- Restructure imphnen-hackathon flat modules into clean architecture
- Remove all stale env vars from .env.example (SurrealDB, QR_JWT, Hackathon infra)
- Fix Dockerfile to include all current workspace crates
- Bump all crate versions 0.2.0 → 0.3.0

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

imphnen-backend/src/bin/api.rs

@@ -1,14 +1,10 @@
-// API entry point using PostgreSQL (SurrealDB migration complete)
-// This file has been updated to use SeaORM with PostgreSQL instead of SurrealDB
-use imphnen_gateway::gateway_service;
-use imphnen_libs::axum_init;
-
-#[tokio::main]
-async fn main() {
-	axum_init(|postgres_db| async {
-		// Gateway service now uses PostgreSQL exclusively (SeaORM)
-		// SurrealDB dependencies have been completely removed
-		gateway_service(postgres_db).await
-	})
-	.await;
-}
+use imphnen_gateway::gateway_service;
+use imphnen_libs::axum_init;
+
+#[tokio::main]
+async fn main() {
+	axum_init(|postgres_db| async {
+		gateway_service(postgres_db).await
+	})
+	.await;
+}