chore(release): 0.68.0 — E2 Feed & Search performance epic

Bump VERSION 0.67.0 -> 0.68.0 and add the user-facing release-notes entry for
the E2 epic (feed sort index, keyset/NOT NULL, search GIN + state inner-joins,
single /feed/summary pass, no card-action refetch storm, job partial indexes).

VERSION

@@ -1 +1 @@
-0.67.0
+0.68.0

frontend/src/lib/releaseNotes.ts

@@ -14,6 +14,22 @@ export interface ReleaseEntry {
 }
 
 export const RELEASE_NOTES: ReleaseEntry[] = [
+  {
+    version: "0.68.0",
+    date: "2026-08-18",
+    summary:
+      "A big performance pass on the feed and search: pages load and search returns near-instantly, even on a large library, and marking videos no longer stutters.",
+    fixes: [
+      "The feed loads much faster. The default “newest” feed and channel pages now use a matching database index instead of scanning the whole video table on every page, so scrolling stays quick even with hundreds of thousands of videos (this was the likely cause of the occasional slow feed).",
+      "Search is dramatically faster — a search that could take several seconds now returns in a fraction of one, and still matches both video text and channel names.",
+      "The Watched / Hidden / In-progress views open faster, and deep scrolling (far down a long feed) no longer slows down page by page.",
+      "Marking a video watched or hidden, and closing the player, no longer briefly reloads the whole feed — the change shows instantly and the list stays put.",
+    ],
+    chores: [
+      "The sidebar's total count and per-tag channel counts now come from a single request + one database pass instead of four, cutting the work done on every filter change.",
+      "The background enrichment and maintenance scans, and the channel search branch, are now index-served instead of full-table scans — much less database load per scheduler run. Backed by new automated equivalence/paging tests and verified end-to-end.",
+    ],
+  },
   {
     version: "0.67.0",
     date: "2026-08-18",