feat: duplicate your own recipe

The fork endpoint already had no "isn't yours" check, so this is a
UI-only change: ForkRecipeButton takes a variant prop ("fork" for
others' recipes, "duplicate" for your own) that swaps icon/label/toast
copy, and now renders unconditionally instead of only for non-owners.

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

apps/web/lib/changelog.ts

@@ -1,5 +1,5 @@
 // Mirrors CHANGELOG.md at the repo root — update both together.
-export const APP_VERSION = "0.19.0";
+export const APP_VERSION = "0.20.0";
 
 export type ChangelogEntry = {
   version: string;
@@ -11,6 +11,13 @@ export type ChangelogEntry = {
 };
 
 export const CHANGELOG: ChangelogEntry[] = [
+  {
+    version: "0.20.0",
+    date: "2026-07-13 22:26",
+    added: [
+      "**Duplicate your own recipe** — same one-click copy used for forking others' recipes, now also on your own, for making variations without touching version history.",
+    ],
+  },
   {
     version: "0.19.0",
     date: "2026-07-13 22:21",