fix: scope Alpine gitea_workspace + commit admin fallback + settings cleanup

1. gitea_workspace.html: owner/repo en Jinja2 dans la topbar (pas Alpine)
2. gitea.py: save_file/delete_file → _require_gitea (admin token can write)
3. settings.html: retrait doublon defaultView, fix workspace_name Jinja2

app/routers/gitea.py

@@ -88,7 +88,7 @@ async def get_file(request: Request, owner: str, repo: str, path: str):
 async def save_file(request: Request, owner: str, repo: str):
     """Create or update a file in the repo."""
     import json
-    gitea = _require_user_gitea(request)
+    gitea = _require_gitea(request)  # admin token can write too
     try:
         body = await request.json()
     except Exception:
@@ -111,7 +111,7 @@ async def save_file(request: Request, owner: str, repo: str):
 async def delete_file(request: Request, owner: str, repo: str):
     """Delete a file from the repo."""
     import json
-    gitea = _require_user_gitea(request)
+    gitea = _require_gitea(request)  # admin token can write too
     path = request.query_params.get("path", "")
     sha = request.query_params.get("sha", "")
     message = request.query_params.get("message", "Delete via FlowDeck")