feat: add call history API endpoints and TTS service client

Adds read-only access to persisted call records for the dashboard
and implements a client for the Rhema text-to-speech service.

- api/call_history.py: New router providing paged call lists
  and detailed call records with transcript metadata.
- services/tts.py: Async client for OpenAI-compatible TTS
  endpoints (Rhema/Kokoro) used for call-flow steps.

main.py

@@ -18,7 +18,7 @@ from contextlib import asynccontextmanager
 from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
 
-from api import calls, call_flows, devices, websocket
+from api import call_flows, call_history, calls, devices, routing, websocket
 from config import get_settings
 from core.gateway import AIPSTNGateway
 from db.database import close_db, init_db
@@ -114,6 +114,7 @@ async def lifespan(app: FastAPI):
     recording_svc = RecordingService()
     await recording_svc.start()
     app.state.recording_service = recording_svc
+    gateway._recording_service = recording_svc
 
     analytics_svc = CallAnalytics()
     app.state.analytics_service = analytics_svc
@@ -171,10 +172,22 @@ app = FastAPI(
 
 # === API Routes ===
 app.include_router(calls.router, prefix="/api/calls", tags=["Calls"])
+app.include_router(call_history.router, prefix="/api/calls", tags=["Call History"])
 app.include_router(call_flows.router, prefix="/api/call-flows", tags=["Call Flows"])
 app.include_router(devices.router, prefix="/api/devices", tags=["Devices"])
+app.include_router(routing.router, prefix="/api/routing", tags=["Routing"])
 app.include_router(websocket.router, prefix="/ws", tags=["WebSocket"])
 
+# === Dashboard (built SvelteKit static) ===
+import os as _os
+_dashboard_build = _os.path.join(_os.path.dirname(__file__), "dashboard", "build")
+if _os.path.isdir(_dashboard_build):
+    app.mount(
+        "/dashboard",
+        StaticFiles(directory=_dashboard_build, html=True),
+        name="dashboard",
+    )
+
 
 # === Root Endpoint ===
 @app.get("/", tags=["System"])