feat: update Steward prompt for clearer delegation instructions

Updates Steward's output format to structured delegation format:
- DELEGATE: [capability] to [action] [task]
- REASON: [explanation]
- COMPLEXITY: [simple/moderate/complex]
- CONTEXT: [relevant history or "none"]

Also adds guidance for conversation memory queries (handled by
Tatlock directly, not delegated to Librarian).

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

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

src/agents/steward/agent.py

@@ -56,6 +56,7 @@ USER QUERY: {query}
 GUIDELINES:
 - Be conservative - only recommend truly necessary capabilities
 - Simple greetings/chat → no capabilities needed (conversational response only)
+- Questions about prior conversation ("what did I say", "my name", "what we discussed") → no capabilities (Tatlock has full history)
 - Math/calculations → tatlock_core
 - Quick web searches → tatlock_core
 - Time/date queries → tatlock_core
@@ -66,11 +67,17 @@ GUIDELINES:
 - If conversation history is relevant, note which previous turns matter
 - Assess complexity: simple (1 tool), moderate (2-3 tools), complex (multiple steps)
 
-RESPOND WITH 2-4 SENTENCES:
-1. Capability needed: name the capability and the specific action (e.g., "librarian to create a wiki page about CI/CD using smart_create")
-2. Reason: brief explanation of why this capability handles the request
-3. Complexity assessment (simple/moderate/complex)
-4. Any relevant conversation context
+RESPOND IN THIS FORMAT:
+DELEGATE: [capability name] to [action] [specific task]
+REASON: [why this capability handles the request]
+COMPLEXITY: [simple/moderate/complex]
+CONTEXT: [any relevant conversation context, or "none"]
+
+EXAMPLES:
+- "DELEGATE: librarian to create a wiki page about CI/CD pipelines"
+- "DELEGATE: librarian to search for information about Docker networking"
+- "DELEGATE: tatlock_core to calculate the result"
+- "DELEGATE: none (conversational response only)"
 
 Be specific about what Tatlock should delegate - include the action verb (create, update, search, etc.).
 Plain text only - no JSON, no special formatting."""