feat: migrate imphnen-backend-qr into workspace as imphnen-qr crate

Ports the Go QR campaign overlay service to a self-contained Rust crate
nested at /v1/qr/... in the gateway.

Features:
- Auth: register, login, Google OAuth, JWT refresh (bcrypt compat with Go DB)
- Users: profile management + admin CRUD (list/role/delete)
- Campaigns: create (auto-generates QR PNG via qrcode crate), list,
  activate, delete; process-image endpoint overlays active campaign QR
  onto uploaded images (bottom-right corner, image crate)
- QR pool connects to imphnen_qr database via QR_DATABASE_URL

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

imphnen-qr/src/auth/infrastructure/http/handlers.rs

@@ -0,0 +1,72 @@
+use axum::{Extension, Json, response::IntoResponse};
+use axum::extract::Query;
+use std::sync::Arc;
+use serde::Deserialize;
+use imphnen_utils::response_format::ApiSuccess;
+use imphnen_utils::errors::AppError;
+use crate::auth::domain::service::QrAuthService;
+use crate::config::QrConfig;
+use super::dto::{RegisterRequest, LoginRequest, RefreshRequest, AuthResponse, TokensResponse};
+
+pub async fn register_handler(
+    Extension(service): Extension<Arc<dyn QrAuthService>>,
+    Json(body): Json<RegisterRequest>,
+) -> Result<axum::response::Response, AppError> {
+    let (tokens, user) = service.register(body.email, body.password, body.name).await?;
+    Ok(ApiSuccess(AuthResponse {
+        access_token: tokens.access_token,
+        refresh_token: tokens.refresh_token,
+        user,
+    }).into_response())
+}
+
+pub async fn login_handler(
+    Extension(service): Extension<Arc<dyn QrAuthService>>,
+    Json(body): Json<LoginRequest>,
+) -> Result<axum::response::Response, AppError> {
+    let (tokens, user) = service.login(body.email, body.password).await?;
+    Ok(ApiSuccess(AuthResponse {
+        access_token: tokens.access_token,
+        refresh_token: tokens.refresh_token,
+        user,
+    }).into_response())
+}
+
+pub async fn google_redirect_handler(
+    Extension(config): Extension<Arc<QrConfig>>,
+) -> Result<axum::response::Response, AppError> {
+    let url = format!(
+        "https://accounts.google.com/o/oauth2/v2/auth?client_id={}&redirect_uri={}&response_type=code&scope=email+profile",
+        config.google_client_id,
+        config.google_redirect_url,
+    );
+    Ok(axum::response::Redirect::temporary(&url).into_response())
+}
+
+#[derive(Debug, Deserialize)]
+pub struct GoogleCallbackQuery {
+    pub code: String,
+}
+
+pub async fn google_callback_handler(
+    Extension(service): Extension<Arc<dyn QrAuthService>>,
+    Query(params): Query<GoogleCallbackQuery>,
+) -> Result<axum::response::Response, AppError> {
+    let (tokens, user) = service.google_callback(params.code).await?;
+    Ok(ApiSuccess(AuthResponse {
+        access_token: tokens.access_token,
+        refresh_token: tokens.refresh_token,
+        user,
+    }).into_response())
+}
+
+pub async fn refresh_handler(
+    Extension(service): Extension<Arc<dyn QrAuthService>>,
+    Json(body): Json<RefreshRequest>,
+) -> Result<axum::response::Response, AppError> {
+    let tokens = service.refresh_token(body.refresh_token).await?;
+    Ok(ApiSuccess(TokensResponse {
+        access_token: tokens.access_token,
+        refresh_token: tokens.refresh_token,
+    }).into_response())
+}