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-backend-hnsw/CMakeLists.txt

@@ -29,12 +29,25 @@ if(APPLE)
     set(CMAKE_OSX_DEPLOYMENT_TARGET "11.0" CACHE STRING "Minimum macOS version")
 endif()
 
-# Use system ZeroMQ instead of building from source
+# Find ZMQ using pkg-config with IMPORTED_TARGET for automatic target creation
 find_package(PkgConfig REQUIRED)
-pkg_check_modules(ZMQ REQUIRED libzmq)
+
+# On ARM64 macOS, ensure pkg-config finds ARM64 Homebrew packages first
+if(APPLE AND CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64|arm64")
+    set(ENV{PKG_CONFIG_PATH} "/opt/homebrew/lib/pkgconfig:/opt/homebrew/share/pkgconfig:$ENV{PKG_CONFIG_PATH}")
+endif()
+
+pkg_check_modules(ZMQ REQUIRED IMPORTED_TARGET libzmq)
+
+# This creates PkgConfig::ZMQ target automatically with correct properties
+if(TARGET PkgConfig::ZMQ)
+    message(STATUS "Found and configured ZMQ target: PkgConfig::ZMQ")
+else()
+    message(FATAL_ERROR "pkg_check_modules did not create IMPORTED target for ZMQ.")
+endif()
 
 # Add cppzmq headers
-include_directories(third_party/cppzmq)
+include_directories(SYSTEM third_party/cppzmq)
 
 # Configure msgpack-c - disable boost dependency
 set(MSGPACK_USE_BOOST OFF CACHE BOOL "" FORCE)