feat(v5.2.0): finalize Infrastructure & Polish (tests isolation, xdist, lint, CI)

tests/conftest.py: mutate the settings singleton (instead of rebinding) so DB + backup dir are isolated per test -> pytest-xdist safe.
Real backup tests (snapshot/prune/admin API) and OAuth mock tests (Gitea/GitHub/link) replace the previous skips.
init_db() now also creates webhook_subscriptions (full schema without the FastAPI lifespan).
ruff check is clean; .eslintrc.json migrated to eslint.config.mjs (flat config).
CI: lint job (ruff + eslint), parallel tests (-n auto), run on every branch push.
VERSION 5.11.1.

app/routers/dashboard.py

@@ -217,7 +217,7 @@ def _sidebar_data(request: Request, repos: list[dict], include_workspace: bool =
         from app.routers.board import _load_shared_sidebar_pages
         shared_made_pages, shared_received_pages, published_pages, shared_pages = _load_shared_sidebar_pages(user["id"])
 
-    return {
+    sidebar = {
         "workspace_name": ws, "workspace_initial": initial,
         "active_ws_name": active_ws_name,
         "workspace_key": f"{gitea_owner}/{gitea_repo}" if gitea_workspace else "",
@@ -937,7 +937,7 @@ async def remove_member(request: Request, ws_id: int, user_id: int):
 @router.get("/local-workspace", response_class=HTMLResponse)
 async def local_workspace_page(request: Request, folder: int = None):
     """Local workspace page with file/folder tree.
-    
+
     If ?folder=ID is provided, shows that folder's contents with breadcrumb.
     """
     from jinja2 import Environment, FileSystemLoader
@@ -984,7 +984,7 @@ async def local_workspace_page(request: Request, folder: int = None):
 @router.get("/api/local-workspace/tree")
 async def local_workspace_tree(request: Request, folder: int = None):
     """Return the file/folder tree filtered by active workspace.
-    
+
     If ?folder=ID is provided, returns only that folder's children.
     Otherwise returns the full recursive tree from root.
     """
@@ -1965,7 +1965,7 @@ async def update_account(request: Request):
 @router.get("/api/sidebar/workspace-tree")
 async def sidebar_workspace_tree(request: Request):
     """Return the sidebar workspace tree as HTML fragment.
-    
+
     Called by appState().refreshSidebarTree() after CRUD operations
     in the main content area to keep the sidebar in sync.
     """
@@ -2296,7 +2296,7 @@ async def api_trash_page(page_id: int):
 @router.post("/api/pages/{page_id:int}/convert-to-database")
 async def api_convert_to_database(page_id: int, request: Request):
     """Convert a page into a full-page database (Notion-style).
-    
+
     Creates a collection linked to this page, adds the default 'Name' property,
     and sets the page's content_format to 'collection'.
     """