feat: add vector sync processing status to /user/page endpoint

Add real-time processing status display to the browser UI at /user/page
showing indexed document count, pending queue size, and sync status.
Implements the status display described in ADR-007 lines 280-298.

Changes:
- Store document_queue and related state in app.state for route access
- Add _get_processing_status() helper to query Qdrant and check queue
- Display status section in user_info_html() with indexed/pending counts
- Show color-coded status badge (green "Idle" or orange "Syncing")
- Only displays when VECTOR_SYNC_ENABLED=true

Status appears in both BasicAuth and OAuth modes, positioned after
session info but before logout buttons. Numbers are formatted with
commas for readability.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

nextcloud_mcp_server/app.py

@@ -1026,6 +1026,22 @@ def get_app(transport: str = "sse", enabled_apps: list[str] | None = None):
                 shutdown_event = anyio_module.Event()
                 scanner_wake_event = anyio_module.Event()
 
+                # Store in app state for access from routes (ADR-007)
+                app.state.document_queue = document_queue
+                app.state.shutdown_event = shutdown_event
+                app.state.scanner_wake_event = scanner_wake_event
+
+                # Also share with browser_app for /user/page route
+                for route in app.routes:
+                    if isinstance(route, Mount) and route.path == "/user":
+                        route.app.state.document_queue = document_queue
+                        route.app.state.shutdown_event = shutdown_event
+                        route.app.state.scanner_wake_event = scanner_wake_event
+                        logger.info(
+                            "Vector sync state shared with browser_app for /user/page"
+                        )
+                        break
+
                 # Start background tasks using anyio TaskGroup
                 async with anyio_module.create_task_group() as tg:
                     # Start scanner task