feat(homepage): open-notebook card, hidden until the service is deployed

Internal-only: port 8502 direct, no vhost field, no Caddy change — exposure
stays behind an explicit decision, and the app carries its own password.

urlStatus=hidden is deliberate: the homepage probe runs on the gateway and the
pair is not deployed, so a live card would render dead on day one. Flipping it
to live is the only homepage change the deploy needs; the seam asserts the
hidden state while the service is repo-only and requires the required card
fields either way.

mono-on.svg follows the mono-* icon set the sibling cards use, so the card does
not fall back to the generic dot.

shared/homepage/services.json

@@ -28,6 +28,19 @@
     "art_bg": "#f5f5f5",
     "warn": "Chats stay on Frank's server, but OpenWebUI's web search rides the same SearXNG path as the search app: obfuscated, not anonymous. The upstream search API keys are tied to Frank’s identity."
   },
+  {
+    "name": "open-notebook",
+    "category": "user",
+    "section": "AI",
+    "description": "Podcast generator — notes in, spoken episode out: script written by frank-zealot, voices rendered by frank-tts. No public route; LAN UI only once it is deployed.",
+    "url": "",
+    "docs": "",
+    "probe": "127.0.0.1:8502",
+    "method": "http",
+    "wip": "down",
+    "showLink": false,
+    "art": "/img/apps/mono-on.svg"
+  },
   {
     "name": "Gitea",
     "category": "user",