fix: serve slides assets in app

app/main.py

@@ -1,7 +1,7 @@
 from pathlib import Path
 
 from fastapi import FastAPI
-from fastapi.responses import FileResponse
+from fastapi.responses import FileResponse, RedirectResponse
 from fastapi.staticfiles import StaticFiles
 
 from app.websocket.chat import router as chat_router
@@ -9,6 +9,7 @@ from app.websocket.manager import manager
 
 BASE_DIR = Path(__file__).resolve().parent
 STATIC_DIR = BASE_DIR / "static"
+SLIDES_DIR = BASE_DIR.parent / "docs" / "slides"
 
 app = FastAPI(title="Simple WebSocket Chatroom")
 
@@ -20,6 +21,17 @@ app.include_router(chat_router)
 app.mount("/static", StaticFiles(directory=STATIC_DIR), name="static")
 
 
+@app.get("/slides", include_in_schema=False)
+async def slides_redirect():
+    """Redirect to the static slides directory so relative asset paths work."""
+    return RedirectResponse(url="/slides/")
+
+
+# Serves the presentation and its relative assets.
+# This keeps docs/slides/index.html openable directly from the file system too.
+app.mount("/slides", StaticFiles(directory=SLIDES_DIR, html=True), name="slides")
+
+
 @app.get("/")
 async def home():
     """Serve the chatroom GUI."""