feat: in-app support form with email + Gitea issue integration (v0.49.0)

Users can now report bugs, suggestions, or questions from a new /support
page. Each submission sends a confirmation email and, when GITEA_URL/
GITEA_TOKEN/GITEA_REPO are configured in admin Settings, opens a labeled
issue on that repo automatically (best-effort — failure doesn't block the
ticket). Admins get a Support section to triage status and retry failed
Gitea issue creation.

New support_tickets table, gitea.ts client, site-settings entries for the
three new secrets, and OpenAPI docs for the two user-facing endpoints.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/components/layout/nav.tsx

@@ -3,7 +3,7 @@
 import Link from "next/link";
 import { usePathname, useRouter } from "next/navigation";
 import { useTheme } from "next-themes";
-import { BookOpen, Calendar, Package, ChefHat, User, FolderOpen, ShoppingCart, Shield, Search, Compass, Menu, Sun, Moon, Monitor, Apple } from "lucide-react";
+import { BookOpen, Calendar, Package, ChefHat, User, FolderOpen, ShoppingCart, Shield, Search, Compass, Menu, Sun, Moon, Monitor, Apple, LifeBuoy } from "lucide-react";
 import { cn } from "@/lib/utils";
 import { Button, buttonVariants } from "@/components/ui/button";
 import {
@@ -130,6 +130,12 @@ export function Nav() {
               <DropdownMenuItem>
                 <Link href="/settings" className="w-full">{t("settings")}</Link>
               </DropdownMenuItem>
+              <DropdownMenuItem>
+                <Link href="/support" className="w-full flex items-center gap-2">
+                  <LifeBuoy className="h-3.5 w-3.5" />
+                  {t("support")}
+                </Link>
+              </DropdownMenuItem>
               <div
                 role="group"
                 aria-label={t("systemMode")}