fix(gui): revert port to 8000, use 302 for setup gate redirect

- Revert uvicorn port from 8088 to 8000 (1b-1 pinned value)
- Change SetupGateMiddleware redirect from 307 to 302 for consistency
  with all other redirects in the codebase

Port 8000 confirmed free on CT104. Earlier change to 8088 was
incorrect — 8080 is held by NATS WebSocket, not 8000.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/central/gui/__init__.py

@@ -169,7 +169,7 @@ def main() -> None:
     uvicorn.run(
         "central.gui:app",
         host="0.0.0.0",
-        port=8088,
+        port=8000,
         reload=False,
     )
 

src/central/gui/middleware.py

@@ -57,7 +57,7 @@ class SetupGateMiddleware(BaseHTTPMiddleware):
         if not setup_complete:
             # Setup not complete - only allow exempt paths
             if not _is_exempt(path, SETUP_EXEMPT_PATHS, SETUP_EXEMPT_PREFIXES):
-                return RedirectResponse(url="/setup", status_code=307)
+                return RedirectResponse(url="/setup", status_code=302)
         else:
             # Setup complete - redirect /setup to /
             if path == "/setup":