feat: add changelog and versioning, surface it in admin

Bumps version to 0.2.0 (root + apps/web package.json) and adds
CHANGELOG.md as the canonical human-readable history, mirrored by
apps/web/lib/changelog.ts as the in-app data source (single
ChangelogList component renders both).

- /changelog: user-facing page, linked from the account dropdown.
- /admin/changelog: same list, plus a "Version" card on the admin
  overview dashboard linking to it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/components/shared/changelog-list.tsx

@@ -0,0 +1,40 @@
+import { Badge } from "@/components/ui/badge";
+import { Separator } from "@/components/ui/separator";
+import { CHANGELOG } from "@/lib/changelog";
+
+export function ChangelogList() {
+  return (
+    <div className="space-y-8 max-w-2xl">
+      {CHANGELOG.map((entry, i) => (
+        <div key={entry.version} className="space-y-3">
+          <div className="flex items-center gap-2">
+            <Badge variant={i === 0 ? "default" : "secondary"}>v{entry.version}</Badge>
+            <span className="text-sm text-muted-foreground">{entry.date}</span>
+          </div>
+
+          {entry.notes && <p className="text-sm text-muted-foreground">{entry.notes}</p>}
+
+          {entry.added && entry.added.length > 0 && (
+            <div className="space-y-1.5">
+              <p className="text-xs font-medium uppercase tracking-wide text-muted-foreground">Added</p>
+              <ul className="space-y-1 text-sm list-disc pl-5">
+                {entry.added.map((line, j) => <li key={j}>{line}</li>)}
+              </ul>
+            </div>
+          )}
+
+          {entry.fixed && entry.fixed.length > 0 && (
+            <div className="space-y-1.5">
+              <p className="text-xs font-medium uppercase tracking-wide text-muted-foreground">Fixed</p>
+              <ul className="space-y-1 text-sm list-disc pl-5">
+                {entry.fixed.map((line, j) => <li key={j}>{line}</li>)}
+              </ul>
+            </div>
+          )}
+
+          {i < CHANGELOG.length - 1 && <Separator className="mt-6" />}
+        </div>
+      ))}
+    </div>
+  );
+}