feat(docker): Add temperature and base_url parameters for LLM configuration. ref #1035

Implement hierarchical configuration for LLM parameters with support for:
  - Temperature control (0.0-2.0) to adjust response creativity
  - Custom base_url for proxy servers and alternative endpoints
  - 4-tier priority: request params > provider env > global env > defaults

  Add helper functions in utils.py, update API schemas and handlers,
  support environment variables (LLM_TEMPERATURE, OPENAI_TEMPERATURE, etc.),
  and provide comprehensive documentation with examples.

deploy/docker/schemas.py

@@ -16,6 +16,8 @@ class MarkdownRequest(BaseModel):
     q:   Optional[str] = Field(None,  description="Query string used by BM25/LLM filters")
     c:   Optional[str] = Field("0",   description="Cache‑bust / revision counter")
     provider: Optional[str] = Field(None, description="LLM provider override (e.g., 'anthropic/claude-3-opus')")
+    temperature: Optional[float] = Field(None, description="LLM temperature override (0.0-2.0)")
+    base_url: Optional[str] = Field(None, description="LLM API base URL override")
 
 
 class RawCode(BaseModel):