Add Relays group (chat/file/message) + faded homepage dividers

New collapsible 'Relays' group in the sidebar (chat/file/message relay) that
expands to show its items and persists open state. Homepage gets a matching
Relays card group, and areas are now split by faded separator bars like the
sidebar. Relay pages are placeholder 'coming soon' stubs (/relays/{kind}).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

manager/main.py

@@ -144,6 +144,20 @@ async def bots_page(request: Request):
     })
 
 
+RELAY_KINDS = {"chat": "Chat relay", "file": "File relay", "message": "Message relay"}
+
+
+@app.get("/relays/{kind}", response_class=HTMLResponse)
+async def relay_page(request: Request, kind: str):
+    if redir := _redirect_if_unauth(request):
+        return redir
+    if kind not in RELAY_KINDS:
+        raise HTTPException(status_code=404, detail="Unknown relay")
+    return TEMPLATES.TemplateResponse(request, "relay.html", {
+        "nav_active": "relays", "kind": kind, "title": RELAY_KINDS[kind],
+    })
+
+
 @app.get("/settings", response_class=HTMLResponse)
 async def settings_page(request: Request):
     if redir := _redirect_if_unauth(request):