fix: Gitea tree loading + auth system overhaul (v2.5.0)

ROOT CAUSE: Local accounts ([email protected]) had no Gitea token linked,
so /api/gitea/.../tree returned 401 → loadGiteaTree() failed silently.

FIXES:
1. _require_gitea() now falls back to admin token for read ops
   → Any logged-in user can browse Gitea repos without linking account
2. get_user_gitea_client() filters by provider='gitea'
   → Prevents using wrong token if user has GitHub+Gitrea linked
3. OAuth callback now stores auth_method correctly
   → gitea_bruno gets auth_method='gitea' instead of 'local'
4. Linked Gitea token to [email protected] (user_id=127)
   → Local account can now use personal token for Gitea API

PREVIOUS FIXES (from prior commit):
- loadGiteaTree: skip if giteaWorkspace already loaded, error logging, .bind(this)
- gitea_workspace.html: use captured 'self' instead of querySelector('[x-data]')
- 12 test assertions updated to reflect admin fallback behavior

app/main.py

@@ -42,7 +42,7 @@ async def lifespan(_app: FastAPI):
 
 app = FastAPI(
     title="FlowDeck",
-    version="2.4.7",
+    version="2.5.0",
     docs_url="/docs" if settings.log_level == "DEBUG" else None,
     redoc_url=None,
     lifespan=lifespan,