Initial MCM project: FastAPI + Textual TUI unified messenger

MultiCustomerMessenger supporting Telegram (python-telegram-bot),
WhatsApp (Green API) and SMS (python-gsmmodem-new). REST API with
Bearer-token auth, SQLAlchemy models for MariaDB, APScheduler for
background polling, and Textual TUI running in same asyncio event-loop.

api/app.py

@@ -0,0 +1,33 @@
+from datetime import datetime
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from api.routes import channels, contacts, conversations, messages
+
+app = FastAPI(
+    title="MCM – MultiCustomerMessenger API",
+    description="Unified messaging gateway for Telegram, WhatsApp and SMS",
+    version="1.0.0",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Routen
+app.include_router(messages.router, prefix="/api/v1")
+app.include_router(conversations.router, prefix="/api/v1")
+app.include_router(contacts.router, prefix="/api/v1")
+app.include_router(channels.router, prefix="/api/v1")
+
+
+@app.get("/health", tags=["system"])
+def health():
+    return {"status": "ok", "service": "MCM", "timestamp": datetime.utcnow().isoformat()}