feat: custom recipe cover color/icon + mute auto placeholder palette (v0.51.0)

Two changes to the no-photo cover placeholder shipped last version:

1. Muted the gradient palette (100/40-opacity tints instead of solid -200/
   -950 stops) — the original was too saturated next to real cover photos
   in the same grid, per feedback.
2. New coverIcon/coverColor columns on recipes (nullable text, migration
   0048, additive-only) let the author pin a specific color+icon from the
   recipe editor instead of the automatic per-id pick. getRecipePlaceholder
   now checks these first, falling back to the deterministic hash pick when
   unset — existing recipes are unaffected until edited.

Wired coverIcon/coverColor through every explicit-column recipe select
that feeds a grid card (explore trending/recent, search, feed, for-you) —
the relational-query call sites (recipes page, collections, profile pages)
already return all columns and needed no changes.

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 = "0.50.2";
+export const APP_VERSION = "0.51.0";
 
 export type ChangelogEntry = {
   version: string;
@@ -11,6 +11,13 @@ export type ChangelogEntry = {
 };
 
 export const CHANGELOG: ChangelogEntry[] = [
+  {
+    version: "0.51.0",
+    date: "2026-07-19 11:40",
+    added: [
+      "Pick your own recipe cover color + icon in the recipe editor (below Photos) — used whenever that recipe has no photo. Also toned down the auto-generated placeholder colors from the previous release, which were too saturated next to real cover photos.",
+    ],
+  },
   {
     version: "0.50.2",
     date: "2026-07-19 10:15",