feat: implement Phase 2 two-tier architecture with Steward

Add comprehensive two-tier architecture where Steward analyzes requests
and Tatlock executes with scoped tools. Includes full infrastructure for
request preprocessing, tool tracking, benchmarking, and streaming.

**Added:**
- Steward agent for request analysis and capability recommendation
- Household Registry for centralized capability management
- Request preprocessing pipeline (Steward → Tatlock flow)
- Tool usage tracking and benchmarking system
- Streaming transparency (Steward reasoning visible in streams)
- Structured logging with operation timing
- Redis benchmark storage with 30-day expiry
- Benchmark analysis CLI tools

**Infrastructure:**
- src/agents/steward/ - Steward agent implementation
- src/agents/tatlock_core/ - Tatlock capability domain
- src/core/preprocessing.py - Request preprocessing pipeline
- src/core/tool_tracking.py - Tool call tracking
- src/core/benchmarks.py - Benchmark recording system
- src/core/household_registry.py - Capability registry
- src/core/startup.py - Application startup coordination
- src/core/logging_config.py - Structured logging setup

**Integration:**
- Responses API uses Steward for Tatlock requests
- Chat Completions wraps Responses API for OpenAI compatibility
- Streaming coordinator supports Steward + Tatlock flow
- Tool scoping per request based on Steward recommendations

**Testing:**
- Integration tests for Steward-Tatlock flow
- Benchmark and registry unit tests
- Steward streaming tests

See PHASE2_PLAN.md and PHASE2_COMPLETE.md for detailed documentation.

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

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

src/core/config.py

@@ -69,9 +69,28 @@ class Config(BaseSettings):
         description="SearXNG request timeout in seconds"
     )
 
+    # Redis Configuration
+    REDIS_HOST: str = Field(
+        default="localhost",
+        description="Redis server host"
+    )
+    REDIS_PORT: int = Field(
+        default=6379,
+        description="Redis server port"
+    )
+    REDIS_DB: int = Field(
+        default=1,
+        description="Redis database number"
+    )
+    REDIS_TIMEOUT: int = Field(
+        default=5,
+        description="Redis connection timeout in seconds"
+    )
+
     # Logging
     LOG_LEVEL: str = Field(default="INFO", description="Logging level")
-    
+    ENABLE_BENCHMARKS: bool = Field(default=True, description="Enable performance benchmarking")
+
     # CORS
     CORS_ORIGINS: list[str] = Field(
         default=["*"],
@@ -81,6 +100,21 @@ class Config(BaseSettings):
     CORS_ALLOW_METHODS: list[str] = ["*"]
     CORS_ALLOW_HEADERS: list[str] = ["*"]
 
+    @property
+    def redis_url(self) -> str:
+        """Construct Redis connection URL."""
+        return f"redis://{self.REDIS_HOST}:{self.REDIS_PORT}/{self.REDIS_DB}"
+
+    @property
+    def log_format(self) -> str:
+        """
+        Determine log format based on environment.
+
+        - production: JSON format for machine parsing
+        - development/testing: Console format for human readability
+        """
+        return "json" if self.ENVIRONMENT == Environment.PRODUCTION else "console"
+
 
 @lru_cache
 def get_config() -> Config: