feat: Add unified LiteLLM API management with dashboard UI and CLI integration

- Create ccw-litellm Python package with AbstractEmbedder and AbstractLLMClient interfaces
- Add BaseEmbedder abstraction and factory pattern to codex-lens for pluggable backends
- Implement API Settings dashboard page for provider credentials and custom endpoints
- Add REST API routes for CRUD operations on providers and endpoints
- Extend CLI with --model parameter for custom endpoint routing
- Integrate existing context-cache for @pattern file resolution
- Add provider model registry with predefined models per provider type
- Include i18n translations (en/zh) for all new UI elements

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ccw-litellm/README.md

@@ -0,0 +1,180 @@
+# ccw-litellm
+
+Unified LiteLLM interface layer shared by ccw and codex-lens projects.
+
+## Features
+
+- **Unified LLM Interface**: Abstract interface for LLM operations (chat, completion)
+- **Unified Embedding Interface**: Abstract interface for text embeddings
+- **Multi-Provider Support**: OpenAI, Anthropic, Azure, and more via LiteLLM
+- **Configuration Management**: YAML-based configuration with environment variable substitution
+- **Type Safety**: Full type annotations with Pydantic models
+
+## Installation
+
+```bash
+pip install -e .
+```
+
+## Quick Start
+
+### Configuration
+
+Create a configuration file at `~/.ccw/config/litellm-config.yaml`:
+
+```yaml
+version: 1
+default_provider: openai
+
+providers:
+  openai:
+    api_key: ${OPENAI_API_KEY}
+    api_base: https://api.openai.com/v1
+
+llm_models:
+  default:
+    provider: openai
+    model: gpt-4
+
+embedding_models:
+  default:
+    provider: openai
+    model: text-embedding-3-small
+    dimensions: 1536
+```
+
+### Usage
+
+#### LLM Client
+
+```python
+from ccw_litellm import LiteLLMClient, ChatMessage
+
+# Initialize client with default model
+client = LiteLLMClient(model="default")
+
+# Chat completion
+messages = [
+    ChatMessage(role="user", content="Hello, how are you?")
+]
+response = client.chat(messages)
+print(response.content)
+
+# Text completion
+response = client.complete("Once upon a time")
+print(response.content)
+```
+
+#### Embedder
+
+```python
+from ccw_litellm import LiteLLMEmbedder
+
+# Initialize embedder with default model
+embedder = LiteLLMEmbedder(model="default")
+
+# Embed single text
+vector = embedder.embed("Hello world")
+print(vector.shape)  # (1, 1536)
+
+# Embed multiple texts
+vectors = embedder.embed(["Text 1", "Text 2", "Text 3"])
+print(vectors.shape)  # (3, 1536)
+```
+
+#### Custom Configuration
+
+```python
+from ccw_litellm import LiteLLMClient, load_config
+
+# Load custom configuration
+config = load_config("/path/to/custom-config.yaml")
+
+# Use custom configuration
+client = LiteLLMClient(model="fast", config=config)
+```
+
+## Configuration Reference
+
+### Provider Configuration
+
+```yaml
+providers:
+  <provider_name>:
+    api_key: <api_key_or_${ENV_VAR}>
+    api_base: <base_url>
+```
+
+Supported providers: `openai`, `anthropic`, `azure`, `vertex_ai`, `bedrock`, etc.
+
+### LLM Model Configuration
+
+```yaml
+llm_models:
+  <model_name>:
+    provider: <provider_name>
+    model: <model_identifier>
+```
+
+### Embedding Model Configuration
+
+```yaml
+embedding_models:
+  <model_name>:
+    provider: <provider_name>
+    model: <model_identifier>
+    dimensions: <embedding_dimensions>
+```
+
+## Environment Variables
+
+The configuration supports environment variable substitution using the `${VAR}` or `${VAR:-default}` syntax:
+
+```yaml
+providers:
+  openai:
+    api_key: ${OPENAI_API_KEY}              # Required
+    api_base: ${OPENAI_API_BASE:-https://api.openai.com/v1}  # With default
+```
+
+## API Reference
+
+### Interfaces
+
+- `AbstractLLMClient`: Abstract base class for LLM clients
+- `AbstractEmbedder`: Abstract base class for embedders
+- `ChatMessage`: Message data class (role, content)
+- `LLMResponse`: Response data class (content, raw)
+
+### Implementations
+
+- `LiteLLMClient`: LiteLLM implementation of AbstractLLMClient
+- `LiteLLMEmbedder`: LiteLLM implementation of AbstractEmbedder
+
+### Configuration
+
+- `LiteLLMConfig`: Root configuration model
+- `ProviderConfig`: Provider configuration model
+- `LLMModelConfig`: LLM model configuration model
+- `EmbeddingModelConfig`: Embedding model configuration model
+- `load_config(path)`: Load configuration from YAML file
+- `get_config(path, reload)`: Get global configuration singleton
+- `reset_config()`: Reset global configuration (for testing)
+
+## Development
+
+### Running Tests
+
+```bash
+pytest tests/ -v
+```
+
+### Type Checking
+
+```bash
+mypy src/ccw_litellm
+```
+
+## License
+
+MIT