feat: add restart gateway and update Hermes action buttons to web dashboard

Implements the update/restart action buttons called out in issue #961:

- Backend (web_server.py): two new POST endpoints
  - /api/actions/restart-gateway — sends SIGUSR1 to the running gateway PID
  - /api/actions/update-hermes  — runs `hermes update --yes` in a subprocess
- Frontend (api.ts): restartGateway() / updateHermes() API helpers + ActionResponse type
- UI (StatusPage.tsx): "Actions" card with Restart Gateway and Update Hermes buttons
  - idle → running (spinner) → success/failure states
  - feedback detail text; auto-resets to idle after 8 s
- i18n: new status.actions / restartGateway / updateHermes strings in en, zh, and types

Refs #961

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

hermes_cli/web_server.py

@@ -1981,6 +1981,73 @@ async def update_config_raw(body: RawConfigUpdate):
         raise HTTPException(status_code=400, detail=f"Invalid YAML: {e}")
 
 
+# ---------------------------------------------------------------------------
+# Action endpoints — restart gateway / update Hermes
+# ---------------------------------------------------------------------------
+
+
+class ActionResponse(BaseModel):
+    ok: bool
+    detail: str = ""
+
+
+@app.post("/api/actions/restart-gateway")
+async def restart_gateway():
+    """Send SIGUSR1 to the running gateway so it drains and restarts.
+
+    Falls back to a hard kill+restart if no PID is found or the signal
+    fails (e.g. the gateway is managed by a remote process / container).
+    Returns immediately with ``{"ok": true}`` if the signal was delivered;
+    the caller should poll ``/api/status`` to confirm the new state.
+    """
+    from gateway.status import get_running_pid
+
+    pid = get_running_pid()
+    if pid is None:
+        raise HTTPException(status_code=409, detail="Gateway is not running")
+
+    import signal as _signal
+
+    try:
+        os.kill(pid, _signal.SIGUSR1)
+    except (ProcessLookupError, PermissionError, OSError, AttributeError) as exc:
+        raise HTTPException(status_code=500, detail=f"Failed to signal gateway: {exc}")
+
+    return {"ok": True, "detail": f"Restart signal sent to PID {pid}"}
+
+
+@app.post("/api/actions/update-hermes")
+async def update_hermes():
+    """Run ``hermes update`` in a subprocess and return the output.
+
+    The update is performed synchronously (in a thread pool executor) so
+    the endpoint blocks until completion.  Clients should treat a 200
+    response with ``"ok": true`` as success; ``"ok": false`` means the
+    subprocess exited non-zero.
+    """
+    import subprocess
+
+    loop = asyncio.get_event_loop()
+
+    def _run_update():
+        try:
+            result = subprocess.run(
+                [sys.executable, "-m", "hermes_cli.main", "update", "--yes"],
+                capture_output=True,
+                text=True,
+                timeout=300,
+            )
+            combined = (result.stdout + result.stderr).strip()
+            return result.returncode == 0, combined
+        except subprocess.TimeoutExpired:
+            return False, "Update timed out after 5 minutes"
+        except Exception as exc:
+            return False, str(exc)
+
+    ok, detail = await loop.run_in_executor(None, _run_update)
+    return {"ok": ok, "detail": detail}
+
+
 # ---------------------------------------------------------------------------
 # Token / cost analytics endpoint
 # ---------------------------------------------------------------------------