feat(whats-new): remote release notes with dev workspace mode (#1058)

* feat(whats-new): remote release notes with dev workspace mode

Add WHATS_NEW.md, CI whats-new.md asset upload, and client fetch/cache
with embedded fallbacks. Dev and -dev builds read the full file from the
repo for debugging; RC/stable download the release asset on first use.

* fix(whats-new): render ## headings and add changelog tab

Parse h2 sections in release-notes markdown; load changelog alongside
highlights and let users switch views on the What's New page.

* fix(whats-new): prefetch on startup and fix CI typecheck prebuild

Prefetch whats-new asset when the shell loads on RC/stable builds.
Run prebuild:release-notes before tsc and coverage jobs so the
gitignored generated bundle exists in CI.

* docs: CHANGELOG and credits for What's New remote notes (PR #1058)

* fix(whats-new): always slice embedded release notes to current line

Drop full CHANGELOG embed for -dev bundles; tauri:dev still reads live
markdown from the repo. Ignore all of src/generated/ in git.

* fix(whats-new): fetch release asset via Rust to bypass CORS

Route whats-new.md download through fetch_url_bytes; rename the
technical tab label; add fetch unit tests (PR #1058 review).

src/hooks/usePrefetchReleaseNotes.ts

@@ -0,0 +1,17 @@
+import { useEffect } from 'react';
+import { version as appVersion } from '../../package.json';
+import { isWorkspaceReleaseNotesMode } from '../utils/releaseNotes/releaseNotesChannel';
+import { resolveReleaseNotes } from '../utils/releaseNotes/releaseNotesResolve';
+
+/**
+ * Warm the release-notes cache after an update (RC/stable only).
+ * Runs once per app session; resolveReleaseNotes skips network when cached.
+ */
+export function usePrefetchReleaseNotes(version: string = appVersion): void {
+  useEffect(() => {
+    if (isWorkspaceReleaseNotesMode(version)) return;
+    void resolveReleaseNotes(version).catch(() => {
+      /* offline or missing asset — embedded fallback loads on /whats-new */
+    });
+  }, [version]);
+}

src/hooks/useReleaseNotes.ts

@@ -0,0 +1,50 @@
+import { useEffect, useState } from 'react';
+import { version as appVersion } from '../../package.json';
+import {
+  resolveChangelogEntry,
+  resolveReleaseNotes,
+  type ReleaseNotesSource,
+} from '../utils/releaseNotes/releaseNotesResolve';
+import type { ReleaseNotesEntry } from '../utils/releaseNotes/releaseNotesMatch';
+
+export interface UseReleaseNotesResult {
+  loading: boolean;
+  whatsNewEntry: ReleaseNotesEntry | null;
+  changelogEntry: ReleaseNotesEntry | null;
+  whatsNewSource: ReleaseNotesSource;
+}
+
+export function useReleaseNotes(version: string = appVersion): UseReleaseNotesResult {
+  const [loading, setLoading] = useState(true);
+  const [whatsNewEntry, setWhatsNewEntry] = useState<ReleaseNotesEntry | null>(null);
+  const [changelogEntry, setChangelogEntry] = useState<ReleaseNotesEntry | null>(null);
+  const [whatsNewSource, setWhatsNewSource] = useState<ReleaseNotesSource>('empty');
+
+  useEffect(() => {
+    let cancelled = false;
+    setLoading(true);
+
+    Promise.all([resolveReleaseNotes(version), resolveChangelogEntry(version)])
+      .then(([whatsNew, changelog]) => {
+        if (cancelled) return;
+        setWhatsNewEntry(whatsNew.entry);
+        setWhatsNewSource(whatsNew.source);
+        setChangelogEntry(changelog.entry);
+      })
+      .catch(() => {
+        if (cancelled) return;
+        setWhatsNewEntry(null);
+        setChangelogEntry(null);
+        setWhatsNewSource('empty');
+      })
+      .finally(() => {
+        if (!cancelled) setLoading(false);
+      });
+
+    return () => {
+      cancelled = true;
+    };
+  }, [version]);
+
+  return { loading, whatsNewEntry, changelogEntry, whatsNewSource };
+}