fix: optimize Notes API pagination with pruneBefore parameter

The Nextcloud Notes API intentionally returns all note IDs (with only 'id'
field) in the last chunk to enable deletion detection. Without using the
pruneBefore parameter, this causes duplicates - all notes appear with full
data in chunks, then again with minimal data in the last chunk.

This commit implements proper pruneBefore support:
- NotesClient.get_all_notes() now accepts prune_before timestamp parameter
- Scanner calculates max(indexed_at) from Qdrant to use as prune threshold
- Only notes modified after this timestamp are sent with full data
- Deduplication logic handles the API's deletion detection pattern
- Significantly reduces data transfer for incremental syncs

The behavior is documented in Notes API v1 spec - this is not an API bug,
but a feature we weren't utilizing correctly.

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

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

nextcloud_mcp_server/client/notes.py

@@ -18,18 +18,57 @@ class NotesClient(BaseNextcloudClient):
         response = await self._make_request("GET", "/apps/notes/api/v1/settings")
         return response.json()
 
-    async def get_all_notes(self) -> AsyncIterator[Dict[str, Any]]:
-        """Get all notes, yielding them one at a time."""
+    async def get_all_notes(
+        self, prune_before: Optional[int] = None
+    ) -> AsyncIterator[Dict[str, Any]]:
+        """Get all notes, yielding them one at a time.
+
+        The Notes API returns changed notes with full data in chunks, and ALL note IDs
+        (with only 'id' field) in the last chunk for deletion detection. This causes
+        duplicates which we handle by tracking seen IDs (first occurrence with full
+        data is kept, later pruned duplicates are skipped).
+
+        Args:
+            prune_before: Optional Unix timestamp. Notes unchanged since this time
+                         are pruned (only 'id' field returned in last chunk).
+                         Reduces data transfer for large note collections.
+
+        Yields:
+            Note dictionaries with full data (deduplicated).
+        """
         cursor = ""
+        seen_ids: set[int] = set()
 
         while True:
+            params: Dict[str, Any] = {"chunkSize": 10}
+            if cursor:
+                params["chunkCursor"] = cursor
+            if prune_before is not None:
+                params["pruneBefore"] = prune_before
+
             response = await self._make_request(
                 "GET",
                 "/apps/notes/api/v1/notes",
-                params={"chunkSize": 10, "chunkCursor": cursor},
+                params=params,
             )
-            for note in response.json():
+            response_data = response.json()
+
+            for note in response_data:
+                note_id = note.get("id")
+                if note_id is None:
+                    logger.warning(f"Skipping note without ID: {note}")
+                    continue
+
+                # Skip duplicates (API returns all IDs in last chunk for deletion detection)
+                if note_id in seen_ids:
+                    logger.debug(
+                        f"Skipping duplicate note {note_id} (pruned version in last chunk)"
+                    )
+                    continue
+
+                seen_ids.add(note_id)
                 yield note
+
             if "X-Notes-Chunk-Cursor" not in response.headers:
                 break
             cursor = response.headers["X-Notes-Chunk-Cursor"]