feat: cooking history/gallery, unit conversion, nutrition diary, pantry scan, digest cron, nutrition-targeted meal plans

Six M-sized items from HANDOFF.md's new-features backlog:

- Profile tabs: cooking-history stats (total cooked, last-cooked, streak)
  and a "cooked it" photo gallery, both owner-only
- Display-time unit conversion (metric<->imperial) for recipe ingredients,
  respecting each user's unitPref; original value always shown alongside
  the conversion
- Nutrition daily diary: per-day macro totals computed from cooking history
  x recipe nutritionData, compared against user goals
- Pantry scan: real barcode lookup (zxing + Open Food Facts, no API key)
  with an AI-vision fallback for unbarcoded items, always confirm-before-
  insert, both paths tier/rate-limited like other AI features
- Weekly digest email: new followers/comments/ratings + trending recipes,
  sent via a new `cron` Docker stage (alpine+crond+curl) and `digest-cron`
  compose service hitting a bearer-token-protected internal route
- Meal-plan generation can now target a user's nutrition goals as a
  prompt-level nudge (recipes are AI-invented, not DB-sourced, so this
  can't be a hard macro constraint)

Caught a real deploy-breaking issue while adding the cron stage: appending
it after `runner` silently changed the Dockerfile's default build target,
and `web`'s compose config didn't pin one — fixed by pinning `target:
runner` explicitly. Verified with typecheck, lint, and three separate
`docker build --target` runs (runner/cron/migrator) plus `docker compose
config` validation.

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

apps/web/lib/email.ts

@@ -104,6 +104,43 @@ export function notificationEmailHtml(title: string, body: string, url: string)
   );
 }
 
+export function weeklyDigestHtml(opts: {
+  newFollowers: number;
+  newComments: number;
+  newRatings: number;
+  trending: { id: string; title: string }[];
+  baseUrl: string;
+}) {
+  const { newFollowers, newComments, newRatings, trending, baseUrl } = opts;
+
+  const stats = [
+    newFollowers > 0 ? `<strong>${newFollowers}</strong> new follower${newFollowers === 1 ? "" : "s"}` : null,
+    newComments > 0 ? `<strong>${newComments}</strong> new comment${newComments === 1 ? "" : "s"} on your recipes` : null,
+    newRatings > 0 ? `<strong>${newRatings}</strong> new rating${newRatings === 1 ? "" : "s"} on your recipes` : null,
+  ].filter((s): s is string => s !== null);
+
+  const statsHtml = stats.length > 0
+    ? `<ul style="margin:0 0 24px;padding:0 0 0 20px;color:#57534e;line-height:1.8;">
+        ${stats.map((s) => `<li>${s}</li>`).join("")}
+       </ul>`
+    : `<p style="margin:0 0 24px;color:#57534e;line-height:1.6;">Quiet week on your recipes — but here's what's trending.</p>`;
+
+  const trendingHtml = trending.length > 0
+    ? `<h2 style="margin:0 0 8px;font-size:16px;">Trending this week</h2>
+       <ol style="margin:0 0 8px;padding:0 0 0 20px;color:#57534e;line-height:1.8;">
+         ${trending.map((r) => `<li><a href="${baseUrl}/recipes/${r.id}" style="color:#1c1917;">${r.title}</a></li>`).join("")}
+       </ol>`
+    : "";
+
+  return layout(
+    "Your weekly digest — Epicure",
+    `<h1 style="margin:0 0 8px;font-size:24px;">Your week on Epicure</h1>
+     ${statsHtml}
+     ${trendingHtml}
+     ${btn(baseUrl, "Open Epicure")}`
+  );
+}
+
 export function welcomeHtml(name: string) {
   return layout(
     "Welcome to Epicure",