fix: implement deletion grace period and vector sync status tool

This commit addresses issues with vector database synchronization that
were causing test failures:

1. **Deletion Grace Period** (scanner.py)
   - Fixed premature deletion of documents due to pagination cursor
     inconsistencies in Notes API
   - Implemented 2-scan verification with 1.5x scan interval grace period
     (15 seconds default)
   - Documents must be missing for 2 consecutive scans before deletion
   - Documents that reappear are removed from deletion tracking
   - Prevents false deletions during concurrent note creation/indexing

2. **Vector Sync Status Tool** (server/notes.py, models/notes.py)
   - Added nc_notes_get_vector_sync_status MCP tool
   - Returns indexed_count, pending_count, status, and enabled fields
   - Enables tests and clients to wait for vector sync completion
   - Uses lifespan context to access document queue and Qdrant client

3. **Test Improvements** (test_sampling.py, conftest.py)
   - Added temporary_note_factory fixture for creating multiple test notes
   - Updated all sampling tests to wait for vector sync completion
   - Adjusted score_threshold to 0.0 for SimpleEmbeddingProvider
     (feature hashing produces low-quality embeddings)
   - Fixed CallToolResult extraction (removed ["result"] key access)
   - Removed invalid @pytest.mark.asyncio markers (anyio mode)

All integration tests now pass successfully.

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

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

nextcloud_mcp_server/models/notes.py

@@ -146,3 +146,29 @@ class SamplingSearchResponse(BaseResponse):
     stop_reason: Optional[str] = Field(
         default=None, description="Reason generation stopped"
     )
+
+
+class VectorSyncStatusResponse(BaseResponse):
+    """Response for vector sync status.
+
+    Provides information about the current state of vector sync,
+    including how many documents are indexed and how many are pending.
+
+    Attributes:
+        indexed_count: Number of documents in Qdrant vector database
+        pending_count: Number of documents in processing queue
+        status: Current sync status ("idle" or "syncing")
+        enabled: Whether vector sync is enabled
+    """
+
+    indexed_count: int = Field(
+        default=0, description="Number of documents indexed in vector database"
+    )
+    pending_count: int = Field(
+        default=0, description="Number of documents pending processing"
+    )
+    status: str = Field(
+        default="disabled",
+        description='Sync status: "idle", "syncing", or "disabled"',
+    )
+    enabled: bool = Field(default=False, description="Whether vector sync is enabled")