refactor(agents): delete dead coordination/streaming delegation stack

One delegation implementation remains (src/agents/delegation.py).
Removed, after verifying zero live importers post-Phase-A/B:

- src/agents/coordination.py: CoordinationEngine, duplicate
  delegate_to_librarian, AGENT_EXECUTORS/AGENT_STREAM_EXECUTORS
  (only importer was its own test module)
- run_librarian_stream: documented-broken path (Ollama streaming +
  tool call bug, PydanticAI #1292/#2256), only called by the deleted
  coordination engine
- stream_delegate_to_* wrappers + STREAMING_DELEGATION_WRAPPERS and
  the never-parsed __DELEGATION_RESULT__ marker in delegation.py
- HouseholdRegistry.get_streaming_delegation_tools() (no callers)
- tests/agents/test_coordination.py and the wrapper/stream tests

Note: the STREAMING_DELEGATION_WRAPPERS import in
src/responses/streaming.py was already removed by Phase A (7ce1c1a);
nothing to delete there.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QbFZyDvYksazX6nYQYZ67L

src/core/household_registry.py

@@ -273,65 +273,6 @@ class HouseholdRegistry:
 
         return tools
 
-    def get_streaming_delegation_tools(self, names: list[str]) -> list[Any]:
-        """
-        Get streaming delegation wrapper tools for specified capabilities.
-
-        Similar to get_delegation_tools() but returns streaming wrappers
-        that yield butler-perspective think messages during execution.
-
-        These wrappers emit think slugs like:
-        - "Allow me to consult the archives, sir."
-        - "The Librarian has compiled the relevant findings."
-
-        Args:
-            names: List of member names to include
-
-        Returns:
-            List of streaming delegation wrappers and/or raw tools
-
-        Example:
-            >>> tools = registry.get_streaming_delegation_tools(["librarian"])
-            >>> async for chunk in tools[0](task="Search for Docker"):
-            ...     print(chunk)  # Yields think messages then result
-        """
-        from src.agents.delegation import STREAMING_DELEGATION_WRAPPERS
-
-        tools = []
-        for name in names:
-            member = self._members.get(name)
-            if not member:
-                logger.warning(
-                    "household_member_not_found",
-                    requested_name=name,
-                    available_names=list(self._members.keys()),
-                )
-                continue
-
-            # Check if this member has a streaming delegation wrapper
-            if name in STREAMING_DELEGATION_WRAPPERS and member.agent is not None:
-                tools.append(STREAMING_DELEGATION_WRAPPERS[name])
-                logger.debug(
-                    "streaming_delegation_wrapper_added",
-                    member=name,
-                )
-            else:
-                # No agent = direct tools (e.g., tatlock_core)
-                tools.extend(member.tools)
-                logger.debug(
-                    "raw_tools_added",
-                    member=name,
-                    tool_count=len(member.tools),
-                )
-
-        logger.info(
-            "streaming_delegation_tools_created",
-            requested_members=names,
-            total_tools=len(tools),
-        )
-
-        return tools
-
     def list_members(self) -> list[str]:
         """
         List all registered member names.