routers: extract chat + ops from api.py

api.py was 933 lines mixing four distinct concerns: indicators +
news + strategic log (the JSON/HTMX API proper), the chat endpoint
+ its three private helpers (~200 lines), and the two HTML-only ops
endpoints /markets-bar + /health (~150 lines).

Extracted:
- app/routers/chat.py — POST /api/chat + _latest_quotes_by_group_chat,
  _thesis_headlines_for_chat, _month_spend
- app/routers/ops.py — GET /api/markets-bar + GET /api/health +
  _fmt_price helper

Both new routers use the same dependencies=[Depends(require_token)]
as api.py and are mounted at the /api prefix in app/main.py.
URL surface is byte-identical with no externally-visible change.

api.py shrinks to ~620 lines focused on indicators+news+log+settings.

Helpers shared with the original api.py (_md_to_html, _resolve_tone_param)
are imported from app.routers.api where needed in chat.py to avoid
duplication.

Also updated tests/test_chat_and_log_gates.py to mount chat_router
in its local test app, since /api/chat now lives there.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_chat_and_log_gates.py

@@ -23,6 +23,7 @@ def _build_app(tmp_path):
     from app.db import Base
     from app.models import StrategicLog, User
     from app.routers import api as api_router
+    from app.routers import chat as chat_router
 
     engine = create_async_engine(f"sqlite+aiosqlite:///{tmp_path}/gates.db")
     factory = async_sessionmaker(engine, expire_on_commit=False)
@@ -56,6 +57,7 @@ def _build_app(tmp_path):
 
     app = FastAPI()
     app.include_router(api_router.router, prefix="/api")
+    app.include_router(chat_router.router, prefix="/api")
     client = TestClient(app)
     return client, sign_session(1), sign_session(2)