feat(gallery): canonical templates.json catalog API (SoT -> build-time gen)

Emit public/templates.json from app/templates-data.ts (the single source of
truth) via a prebuild step, so gallery.hanzo.ai/templates.json is the
machine-readable template catalog consumed by hanzo.app. Each record keeps
the raw SoT fields and adds absolute screenshotUrl/templateUrl/repo so
consumers never encode the gallery's internal path scheme.

- scripts/gen-templates-json.mjs: imports templates-data.ts (node 24 type-strip)
- package.json: prebuild hook runs the generator before next build
- Dockerfile: node:22 -> node:24 for stable TS type-stripping
- public/templates.json: 72 templates, 71 with real screenshots

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Dockerfile

@@ -3,7 +3,10 @@
 # Two stages: build the export, then re-serve it through the canonical static server.
 
 # 1) Build the Next.js static export -> /app/out
-FROM node:22-bookworm-slim AS build
+# node:24 (LTS) has stable TypeScript type-stripping so the `prebuild` step can
+# `import` app/templates-data.ts directly to emit public/templates.json (the SoT
+# -> canonical catalog API). No flags needed.
+FROM node:24-bookworm-slim AS build
 WORKDIR /app
 COPY package.json package-lock.json ./
 RUN npm ci --no-audit --no-fund

package.json

@@ -4,6 +4,8 @@
   "private": true,
   "scripts": {
     "dev": "next dev --turbopack",
+    "gen-templates-json": "node scripts/gen-templates-json.mjs",
+    "prebuild": "node scripts/gen-templates-json.mjs",
     "build": "next build",
     "start": "next start",
     "lint": "eslint",

scripts/gen-templates-json.mjs

@@ -0,0 +1,49 @@
+#!/usr/bin/env node
+// One source of truth -> canonical catalog API.
+// Reads app/templates-data.ts (the SoT) and emits public/templates.json so
+// gallery.hanzo.ai/templates.json is the machine-readable template catalog
+// consumed by hanzo.app. Run as a prebuild step (npm run build).
+//
+// Each emitted record keeps the raw SoT fields and adds absolute URLs so
+// consumers never have to know the gallery's internal path scheme:
+//   screenshotUrl -> https://gallery.hanzo.ai/screenshots/<screenshot>.png
+//   templateUrl   -> https://gallery.hanzo.ai/templates/<slug>
+//   repo          -> https://github.com/hanzo-apps/<slug>  (fork source)
+
+import { readFileSync, writeFileSync, existsSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, join } from 'node:path';
+import { templates } from '../app/templates-data.ts';
+
+const here = dirname(fileURLToPath(import.meta.url));
+const root = join(here, '..');
+const GALLERY_ORIGIN = process.env.GALLERY_ORIGIN || 'https://gallery.hanzo.ai';
+const screenshotsDir = join(root, 'public', 'screenshots');
+
+const enriched = templates.map((t) => {
+  const shotFile = `${t.screenshot}.png`;
+  const hasShot = existsSync(join(screenshotsDir, shotFile));
+  return {
+    ...t,
+    screenshotUrl: `${GALLERY_ORIGIN}/screenshots/${shotFile}`,
+    hasScreenshot: hasShot,
+    templateUrl: `${GALLERY_ORIGIN}/templates/${t.slug}`,
+    repo: `https://github.com/hanzo-apps/${t.slug}`,
+  };
+});
+
+const withShots = enriched.filter((t) => t.hasScreenshot).length;
+const payload = {
+  version: 1,
+  origin: GALLERY_ORIGIN,
+  count: enriched.length,
+  screenshots: withShots,
+  generatedAt: new Date().toISOString(),
+  templates: enriched,
+};
+
+const out = join(root, 'public', 'templates.json');
+writeFileSync(out, JSON.stringify(payload, null, 2));
+console.log(
+  `gen-templates-json: wrote ${enriched.length} templates (${withShots} with screenshots) -> public/templates.json`,
+);