refactor: replace orchestrator with LangGraph deep-agent supervisors

- Add app/core/deep_agent.py with Home and Floating supervisor graphs
  using LangGraph create_react_agent (hierarchical pattern)
- Strip ChatAgent classes from all 4 agent files, keep @tool functions
- Rewrite output_formatter.py for event-based (token/tool_end/mutations) stream
- Update device_ws.py to use run_home_stream/run_floating_stream
- Rewrite chat.py REST route to use run_home
- Add update_core_memory tool to both supervisors
- Add langgraph>=0.3.0 to requirements.txt
- Remove orchestrator.py, execution_plan.py, agent_registry.py, plans.py
- Remove PlanAction, PlanStep, ExecutionPlan, execution_mode from schemas
- Update all affected tests to match new API
- Remove 6 deprecated test files for deleted modules
- Clean up stale docstrings referencing removed orchestrator

app/agents/project_agent.py

@@ -1,33 +1,13 @@
-"""Project agent — full lifecycle management (list, get, create, update, archive, delete)."""
+"""Project agent — tool definitions for project lifecycle CRUD."""
 
 from __future__ import annotations
 
-import json
 from typing import Any
 
-from langchain_core.messages import HumanMessage, SystemMessage
 from langchain_core.tools import tool
 
-from app.core.agent_registry import ChatAgent, registry
-from app.core.llm import get_llm
 from app.core.ws_context import execute_on_client
 
-_SYSTEM_PROMPT = (
-    "You are a project management assistant. You help users create, find,\n"
-    "update, and archive projects in their workspace.\n\n"
-    "Rules:\n"
-    "  - status must be one of: active, archived\n"
-    "  - client_id is optional; link to a client only when explicitly mentioned\n"
-    "  - ai_summary is populated only when the user asks for a project summary;\n"
-    "    derive it from context data — do not fabricate content\n"
-    "  - Use list_projects for scoped queries; list_all_projects only when the\n"
-    "    user wants a complete cross-client view including archived projects\n"
-    "  - get_project requires a project UUID; resolve the ID first by calling\n"
-    "    list_projects if you only have a project name\n"
-    "  - Prefer archiving (update_project status=archived) over deletion;\n"
-    "    only call delete_project when the user explicitly confirms deletion."
-)
-
 
 @tool
 async def list_projects(
@@ -137,30 +117,4 @@ async def delete_project(project_id: str) -> str:
     return f"Project {project_id} permanently deleted."
 
 
-@registry.register
-class ProjectAgent(ChatAgent):
-    def get_name(self) -> str:
-        return "project_agent"
 
-    def get_description(self) -> str:
-        return "Manages projects: list, get, create, update, archive, delete"
-
-    def get_tools(self) -> list[Any]:
-        return [
-            list_projects,
-            list_all_projects,
-            get_project,
-            create_project,
-            update_project,
-            delete_project,
-        ]
-
-    async def handle(self, query: str, context: dict[str, Any]) -> str:
-        llm = get_llm()
-        messages = [
-            SystemMessage(content=_SYSTEM_PROMPT),
-            HumanMessage(
-                content=f"User query: {query}\nContext: {json.dumps(context)[:1000]}"
-            ),
-        ]
-        return await self._tool_loop(llm, messages, self.get_tools())