chore(release): 0.12.0

Cut a version marker for the accumulated work staged on dev (epics 1-4): reusable
Banner; Discover total-videos column + subscribe confirm; Stats consolidation +
quota-action taxonomy; DB-backed system_config + admin Configuration page. NOT
deployed to prod yet — dev/localdev report 0.12.0, prod stays 0.11.2 until a ship.
Alembic head at this marker: 0021.

frontend/src/lib/releaseNotes.ts

@@ -14,6 +14,20 @@ export interface ReleaseEntry {
 }
 
 export const RELEASE_NOTES: ReleaseEntry[] = [
+  {
+    version: "0.12.0",
+    date: "2026-06-19",
+    summary:
+      "A dedicated Usage & stats page, a live Configuration page for admins, and polish on the channel-discovery list.",
+    features: [
+      "Usage & stats is now its own page (moved out of Settings): see your sync status and your personal API usage at a glance, with a clear, translated breakdown by action. Admins get an extra System tab with the instance-wide quota dashboard and the background-sync pause control.",
+      "“Discover from playlists” now shows each channel's total video count, so you can size it up before following — and subscribing asks for confirmation first, since it changes your real YouTube account and uses a little quota.",
+    ],
+    chores: [
+      "Admins can edit operational settings live from a new Configuration page — email/SMTP, the YouTube API key, the daily quota budget, and backfill/Shorts-probe limits — stored in the database and applied without a redeploy. Secrets (SMTP password, API key) are encrypted and write-only.",
+      "Standardized the names of API-usage actions with full English/Hungarian/German labels, and unified the version/demo banners into one reusable component.",
+    ],
+  },
   {
     version: "0.11.2",
     date: "2026-06-19",