Feature/optimize ollama batching (#152)

* feat: add metadata output to search results

- Add --show-metadata flag to display file paths in search results
- Preserve document metadata (file_path, file_name, timestamps) during chunking
- Update MCP tool schema to support show_metadata parameter
- Enhance CLI search output to display metadata when requested
- Fix pre-existing bug: args.backend -> args.backend_name

Resolves yichuan-w/LEANN#144

* fix: resolve ZMQ linking issues in Python extension

- Use pkg_check_modules IMPORTED_TARGET to create PkgConfig::ZMQ
- Set PKG_CONFIG_PATH to prioritize ARM64 Homebrew on Apple Silicon
- Override macOS -undefined dynamic_lookup to force proper symbol resolution
- Use PUBLIC linkage for ZMQ in faiss library for transitive linking
- Mark cppzmq includes as SYSTEM to suppress warnings

Fixes editable install ZMQ symbol errors while maintaining compatibility
across Linux, macOS Intel, and macOS ARM64 platforms.

* style: apply ruff formatting

* chore: update faiss submodule to use ww2283 fork

Use ww2283/faiss fork with fix/zmq-linking branch to resolve CI checkout
failures. The ZMQ linking fixes are not yet merged upstream.

* feat: implement true batch processing for Ollama embeddings

Migrate from deprecated /api/embeddings to modern /api/embed endpoint
which supports batch inputs. This reduces HTTP overhead by sending
32 texts per request instead of making individual API calls.

Changes:
- Update endpoint from /api/embeddings to /api/embed
- Change parameter from 'prompt' (single) to 'input' (array)
- Update response parsing for batch embeddings array
- Increase timeout to 60s for batch processing
- Improve error handling for batch requests

Performance:
- Reduces API calls by 32x (batch size)
- Eliminates HTTP connection overhead per text
- Note: Ollama still processes batch items sequentially internally

Related: #151

* fall back to original faiss as i merge the PR

---------

Co-authored-by: yichuan520030910320 <yichuan_wang@berkeley.edu>

packages/leann-core/src/leann/mcp.py

@@ -60,6 +60,11 @@ def handle_request(request):
                                     "maximum": 128,
                                     "description": "Search complexity level. Use 16-32 for fast searches (recommended), 64+ for higher precision when needed.",
                                 },
+                                "show_metadata": {
+                                    "type": "boolean",
+                                    "default": False,
+                                    "description": "Include file paths and metadata in search results. Useful for understanding which files contain the results.",
+                                },
                             },
                             "required": ["index_name", "query"],
                         },
@@ -104,6 +109,8 @@ def handle_request(request):
                     f"--complexity={args.get('complexity', 32)}",
                     "--non-interactive",
                 ]
+                if args.get("show_metadata", False):
+                    cmd.append("--show-metadata")
                 result = subprocess.run(cmd, capture_output=True, text=True)
 
             elif tool_name == "leann_list":