feat: add py.typed, Ray handles for clients, and pre-commit config

- Add py.typed marker for PEP 561 type hint support
- Add ray_utils module for Ray handle detection and caching
- Update all clients (Embeddings, LLM, TTS, STT, Reranker) to use
  Ray handles when running inside Ray cluster for faster internal calls
- Add .pre-commit-config.yaml with ruff and standard hooks
- Add pre-commit and ray[serve] to optional dependencies
- Bump ruff version to 0.4.0

.pre-commit-config.yaml

@@ -0,0 +1,32 @@
+# Pre-commit hooks for handler-base
+# Install: pip install pre-commit && pre-commit install
+# Run: pre-commit run --all-files
+
+repos:
+  # Ruff - fast Python linter and formatter
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.4.4
+    hooks:
+      - id: ruff
+        args: [--fix, --exit-non-zero-on-fix]
+      - id: ruff-format
+
+  # Standard pre-commit hooks
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.6.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-added-large-files
+        args: [--maxkb=500]
+      - id: check-merge-conflict
+      - id: detect-private-key
+
+  # Type checking (optional - uncomment when ready)
+  # - repo: https://github.com/pre-commit/mirrors-mypy
+  #   rev: v1.10.0
+  #   hooks:
+  #     - id: mypy
+  #       additional_dependencies: [types-all]
+  #       args: [--ignore-missing-imports]