refactor(search): address PR #750 review feedback

- Cap all_results to limit*2 after sort in the per-doc_types branch of
  nc_semantic_search to bound over-verification (was unbounded N-types).
- Switch BatchVerifier from (client, doc_ids, user_id) to (client, results,
  semaphore). Verifiers now read file paths and deck board/stack ids from
  SearchResult.metadata instead of doing fresh Qdrant scrolls — eliminates
  one duplicate round-trip per file/deck-card verification.
- Bound per-id verification concurrency with a shared anyio.Semaphore
  (default 20, matching server/semantic.py context-expansion convention).
  Prevents httpx pool exhaustion / rate limiting on large search pages.
- Propagate stack_id from Qdrant payload to SearchResult.metadata in both
  bm25_hybrid.py and semantic.py (board_id was already propagated).
- Drop now-unused _resolve_file_path / _resolve_deck_metadata helpers.
- Drop redundant int(d) in requested predicate from _verify_news_items.
- Rewrite eviction comment to be honest about inline (not background)
  execution and the resulting latency coupling.
- ADR-019 status: Proposed -> Accepted.
- Add news property to NextcloudClientProtocol.
- Widen SearchResult.id and SemanticSearchResult.id to int | str to match
  BatchVerifier signature and document support for future string-id types.
- Flip openWorldHint to True on nc_semantic_search_answer (it calls into
  Nextcloud via nc_semantic_search).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nextcloud_mcp_server/server/semantic.py

@@ -142,8 +142,13 @@ def configure_semantic_tools(mcp: FastMCP):
                     )
                     all_results.extend(unverified_results)
 
-                # Sort combined results by score
+                # Sort combined results by score, then cap to `limit * 2` to
+                # match the cross-app branch's over-fetch budget. Without this
+                # cap, N requested doc_types × `limit * 2` results would all
+                # flow into verification, multiplying the Nextcloud round-trip
+                # cost by N.
                 all_results.sort(key=lambda r: r.score, reverse=True)
+                all_results = all_results[: limit * 2]
 
             # ADR-019: Verify-on-read. The vector index is a recall layer;
             # Nextcloud is the source of truth for access. Filter out ghost
@@ -300,7 +305,7 @@ def configure_semantic_tools(mcp: FastMCP):
         title="Search with AI-Generated Answer",
         annotations=ToolAnnotations(
             readOnlyHint=True,  # Search doesn't modify data
-            openWorldHint=False,  # Searches only indexed Nextcloud data
+            openWorldHint=True,  # Calls into Nextcloud via nc_semantic_search
         ),
     )
     @require_scopes("semantic.read")
@@ -432,7 +437,7 @@ def configure_semantic_tools(mcp: FastMCP):
             async with semaphore:
                 if result.doc_type == "note":
                     try:
-                        note = await client.notes.get_note(result.id)
+                        note = await client.notes.get_note(int(result.id))
                         content = note.get("content", "")
                         accessible_results[index] = result
                         full_contents[index] = content