feat: Report Bug button that creates Gitea issues

Adds a 'Report Bug' button to the web UI (top bar) that files an issue
on Gitea via the daemon. The issue body is enriched with auto-collected
context: nvcurve version, hostname, GPU name, applied offset summary,
active profile, and a collapsed tail of the recent server log.

Security model:
- The Gitea token (nvcurve_bot, scope write:issue) is embedded as a
  built-in default so the feature works out of the box for every
  install of this public repo — no configuration required.
- The token is only ever used server-side; it never reaches the
  browser, logs, or API responses.
- The endpoint is behind the existing session auth when enabled, and
  rate-limited to one report per 5 minutes per client IP.
- config.json can override gitea_url/gitea_repo/gitea_token (e.g.
  forks pointing at their own repo); gitea_token: '' disables it.

frontend/src/components/Monitor/StatusBar.tsx

@@ -7,10 +7,13 @@ import {
   ChevronDown,
   LogOut,
   User,
+  Bug,
 } from "lucide-react";
 import type { GpuInfo, MonitoringSample } from "../../types.js";
 import { fmt } from "../../utils/units.js";
 import { useCurveStore } from "../../store/curveStore.js";
+import { api } from "../../api/client.js";
+import { ReportBugDialog } from "../common/ReportBugDialog.js";
 import { useState, useRef, useEffect } from "react";
 
 interface Props {
@@ -43,8 +46,17 @@ export function StatusBar({
   const { availableGpus, selectedGpuIndex, setSelectedGpuIndex } =
     useCurveStore();
   const [isOpen, setIsOpen] = useState(false);
+  const [bugReportConfigured, setBugReportConfigured] = useState(false);
+  const [reportBugOpen, setReportBugOpen] = useState(false);
   const dropdownRef = useRef<HTMLDivElement>(null);
 
+  useEffect(() => {
+    api
+      .reportBugStatus()
+      .then((s) => setBugReportConfigured(s.configured))
+      .catch(() => {});
+  }, []);
+
   useEffect(() => {
     function handleClickOutside(event: MouseEvent) {
       if (
@@ -169,8 +181,18 @@ export function StatusBar({
           />
         </div>
 
-        {/* Right: user + connection status */}
+        {/* Right: report bug + user + connection status */}
         <div className="flex items-center gap-3 shrink-0">
+          {bugReportConfigured && (
+            <button
+              onClick={() => setReportBugOpen(true)}
+              title="Report a bug (creates a Gitea issue)"
+              className="flex items-center gap-1.5 px-2 py-1 rounded hover:bg-zinc-800 text-zinc-400 hover:text-zinc-200 transition-colors"
+            >
+              <Bug size={14} />
+              <span className="hidden sm:inline text-xs">Report Bug</span>
+            </button>
+          )}
           {user && (
             <div className="flex items-center gap-1.5 text-zinc-400">
               <User size={14} className="text-zinc-500" />
@@ -192,6 +214,9 @@ export function StatusBar({
           </div>
         </div>
       </div>
+      {reportBugOpen && (
+        <ReportBugDialog onClose={() => setReportBugOpen(false)} />
+      )}
     </header>
   );
 }