integration: add chat/api/app.py

chat/api/app.py

@@ -0,0 +1,42 @@
+# chat/api/app.py
+"""
+DeepSeek V4 chat standalone FastAPI app.
+
+Run standalone::
+
+    uvicorn chat.api.app:app --host 0.0.0.0 --port 8003
+
+or mount into the Sovereign orchestrator (src/sovereign/main.py) which
+includes chat.api.routes.router under /api/v1/chat.
+"""
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+
+from chat import __brand__, __version__
+from chat.api.routes import router
+
+app = FastAPI(
+    title="DeepSeek V4 Chat API",
+    version=__version__,
+    description=f"{__brand__} — sovereign-tuned conversational core",
+)
+app.include_router(router)
+
+
+@app.get("/")
+def index() -> dict:
+    """Service banner."""
+    return {
+        "service": "chat",
+        "brand": __brand__,
+        "version": __version__,
+        "endpoints": "/api/v1/chat/*",
+    }
+
+
+@app.get("/health")
+def health() -> dict:
+    """Liveness probe."""
+    return {"status": "ok", "brand": __brand__, "version": __version__}