refactor(routes): rename /agents and /agent-setup to /scouts and /scout-setup

Rename routes/agents.py → routes/scouts.py and routes/agent_setup.py →
routes/scout_setup.py. Update APIRouter prefix/tags in scouts.py to
/scouts and scouts. Update main.py router registration, device_ws.py
import, and test_journey_v2.py import/patch paths to use scout_setup.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_journey_v2.py

@@ -37,7 +37,7 @@ from unittest.mock import patch
 import pytest
 import yaml
 
-from app.api.routes.agent_setup import (
+from app.api.routes.scout_setup import (
     _CONFIG_END,
     _CONFIG_START,
     _MAX_TURNS,
@@ -230,7 +230,7 @@ async def test_4_6f_nudge_uses_new_markers():
         # Return plain text — no markers — to trigger the nudge path.
         return "I still need more information from you."
 
-    from app.api.routes.agent_setup import JourneySession
+    from app.api.routes.scout_setup import JourneySession
 
     fake_session = JourneySession(
         session_id=session_id,
@@ -248,7 +248,7 @@ async def test_4_6f_nudge_uses_new_markers():
     _sessions[session_id] = fake_session
 
     try:
-        with patch("app.api.routes.agent_setup._call_llm_with_tools", side_effect=_mock_llm):
+        with patch("app.api.routes.scout_setup._call_llm_with_tools", side_effect=_mock_llm):
             await handle_journey_message(_USER_ID, {
                 "session_id": session_id,
                 "message": "one more message to trigger nudge",