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/agents/steward/agent.py

@@ -0,0 +1,165 @@
+"""
+Steward agent - First-tier request analyzer.
+
+The Steward analyzes incoming requests, identifies relevant household
+capabilities, and provides focused recommendations to Tatlock (the Butler).
+This creates a two-tier architecture that prevents cognitive overload.
+
+Uses plain text output (not JSON) for reliability with Ollama models.
+"""
+import httpx
+from typing import Optional
+
+from src.core.config import config
+from src.core.household_registry import get_household_registry
+from src.core.logging_config import get_logger
+
+logger = get_logger(__name__)
+
+
+# System prompt for plain text recommendations
+def build_steward_prompt(query: str, conversation_history: list[dict]) -> str:
+    """Build the steward's analysis prompt with query and conversation history."""
+
+    # Get available capabilities from registry
+    registry = get_household_registry()
+    capabilities = registry.get_all_capabilities()
+
+    cap_list = []
+    for cap in capabilities:
+        cap_list.append(
+            f"• {cap.name} - {cap.description} (domains: {', '.join(cap.domains)})"
+        )
+    capabilities_text = "\n".join(cap_list)
+
+    # Format conversation history if present
+    history_text = ""
+    if conversation_history:
+        history_lines = []
+        for i, msg in enumerate(conversation_history):
+            role = msg.get("role", "unknown")
+            content = msg.get("content", "")[:100]  # Truncate long messages
+            history_lines.append(f"{i}. {role}: {content}")
+        history_text = "\n\nCONVERSATION HISTORY:\n" + "\n".join(history_lines)
+
+    return f"""You are the Steward of the household, advising the Butler (Tatlock) on which capabilities to use.
+
+AVAILABLE HOUSEHOLD CAPABILITIES:
+{capabilities_text}
+
+YOUR TASK:
+Analyze the user's query and recommend which capabilities are needed.
+{history_text}
+
+USER QUERY: {query}
+
+GUIDELINES:
+- Be conservative - only recommend truly necessary capabilities
+- Simple greetings/chat → no capabilities needed (conversational response only)
+- Math/calculations → tatlock_core
+- Web searches → tatlock_core
+- Time/date queries → tatlock_core
+- If conversation history is relevant, note which previous turns matter
+- Assess complexity: simple (1 tool), moderate (2-3 tools), complex (multiple steps)
+- If capabilities are missing, mention what would be needed
+
+RESPOND WITH 2-3 SENTENCES:
+1. Which capabilities (if any) are needed and why
+2. Complexity assessment (simple/moderate/complex)
+3. Any conversation context or missing capabilities
+
+Use capability names in your response (e.g., "tatlock_core for calculations").
+Plain text only - no JSON, no special formatting."""
+
+
+class StewardAgent:
+    """
+    The Steward - Request analyzer and capability coordinator.
+
+    Analyzes requests with full conversation context and recommends
+    which household capabilities the Butler should use.
+
+    Uses plain text output for reliability with Ollama models.
+    """
+
+    def __init__(self):
+        """Initialize Steward with Ollama model (same as Tatlock for VRAM efficiency)."""
+        self.ollama_host = str(config.OLLAMA_HOST).rstrip('/')
+        self.model_name = config.OLLAMA_DEFAULT_MODEL
+        self.timeout = 30.0  # 30 second timeout for analysis
+
+        logger.info(
+            "steward_agent_created",
+            ollama_host=self.ollama_host,
+            model=self.model_name,
+            timeout=self.timeout,
+        )
+
+    async def analyze(
+        self,
+        query: str,
+        conversation_history: Optional[list[dict]] = None
+    ) -> str:
+        """
+        Analyze query and return plain text recommendation.
+
+        Args:
+            query: User's query to analyze
+            conversation_history: Previous conversation turns
+
+        Returns:
+            Plain text analysis from Steward
+
+        Example:
+            >>> text = await steward.analyze("What's 2 + 2?")
+            >>> print(text)
+            "This requires tatlock_core for mathematical calculations. Complexity: simple."
+        """
+        history = conversation_history or []
+        prompt = build_steward_prompt(query, history)
+
+        logger.debug("steward_calling_ollama", query_preview=query[:100])
+
+        # Call Ollama API directly (more reliable than PydanticAI for plain text)
+        async with httpx.AsyncClient(timeout=self.timeout) as client:
+            response = await client.post(
+                f"{self.ollama_host}/api/generate",
+                json={
+                    "model": self.model_name,
+                    "prompt": prompt,
+                    "stream": False,
+                    "options": {
+                        "temperature": 0.3,  # Lower = more consistent
+                        "top_p": 0.9
+                    }
+                }
+            )
+
+            response.raise_for_status()
+            result = response.json()
+
+            analysis_text = result["response"].strip()
+
+            logger.debug(
+                "steward_analysis_received",
+                text_preview=analysis_text[:150]
+            )
+
+            return analysis_text
+
+
+# Global Steward instance
+_steward_agent = None
+
+
+def get_steward_agent() -> StewardAgent:
+    """
+    Get the global Steward agent instance.
+
+    Returns:
+        StewardAgent instance
+    """
+    global _steward_agent
+    if _steward_agent is None:
+        _steward_agent = StewardAgent()
+    return _steward_agent