v0.88.0: app-email SMTP relay (in-process shim + per-app injection)

In-process go-smtp shim (Shape 1): apps → shim → hub → Resend, Resend key stays
hub-side. From-header allowlist (reject 5xx pre-hub), single-shot raw-MIME forward,
status→SMTP mapping. Global + per-app toggles gate compose-time env injection from
.felhom.yml smtp_mapping. Hungarian UI on settings + app config pages.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

controller/internal/web/tier2_config_handler.go

@@ -93,6 +93,31 @@ func (s *Server) tier2ConfigSaveHandler(w http.ResponseWriter, r *http.Request,
 	s.redirectTier2(w, r, name, "A 2. mentés beállítása elmentve.", "")
 }
 
+// appEmailToggleHandler flips the per-app email toggle (only for apps with an smtp_mapping)
+// and recreates the stack so the SMTP env injection takes effect. Redirects back to the
+// app's config page with a flash.
+func (s *Server) appEmailToggleHandler(w http.ResponseWriter, r *http.Request, name string) {
+	if _, ok := s.stackMgr.GetStack(name); !ok {
+		http.NotFound(w, r)
+		return
+	}
+	_ = r.ParseForm()
+	enabled := r.FormValue("app_email_enabled") == "on" || r.FormValue("app_email_enabled") == "true"
+
+	dest := "/stacks/" + url.PathEscape(name) + "/deploy"
+	if err := s.stackMgr.SetAppEmailEnabled(name, enabled); err != nil {
+		s.logger.Printf("[ERROR] [web] app-email toggle for %s: %v", name, err)
+		http.Redirect(w, r, dest+"?flash_error="+url.QueryEscape(err.Error()), http.StatusSeeOther)
+		return
+	}
+	s.logger.Printf("[INFO] [web] App-email for %s set to %v", name, enabled)
+	msg := "Email-küldés kikapcsolva ennél az alkalmazásnál."
+	if enabled {
+		msg = "Email-küldés bekapcsolva ennél az alkalmazásnál."
+	}
+	http.Redirect(w, r, dest+"?flash="+url.QueryEscape(msg), http.StatusSeeOther)
+}
+
 // redirectTier2 sends the customer back to the panel with a flash message.
 func (s *Server) redirectTier2(w http.ResponseWriter, r *http.Request, name, flash, flashErr string) {
 	dest := "/stacks/" + url.PathEscape(name) + "/backup"