perf(iconify): tree-shake MDI to used icons (-99.5% JSON, -71% client bundle)

The previous setup loaded the full @iconify-json/mdi collection (7000+
icons, 2.95 MB) just to render the ~30 icons we actually use, producing a
2.99 MB client chunk.

generate-icons.mjs scans src/ for static `icon="mdi:..."` references,
extracts a minimal IconifyJSON containing only those icons (plus an
EXTRA_ICONS list for dynamic CMS-driven names) from
@iconify-json/mdi/icons.json, and writes it to a generated subset file.
iconify-offline.ts now registers that subset instead of the full pack.

  build/client: 5.6 MB -> 1.6 MB (-71%)
  build/server: 5.3 MB -> 2.4 MB (-55%)
  largest client chunk: 2.99 MB -> 127 KB (-96%)
  iconify subset: 2.95 MB -> 15.5 KB (-99.5%)

Hooked into predev/prebuild so the subset stays fresh; missing icons
fall back to the iconify API at runtime.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/generate-icons.mjs

@@ -0,0 +1,144 @@
+#!/usr/bin/env node
+/**
+ * Tree-shake @iconify-json/mdi: scan src/ for `icon="mdi:..."` references and
+ * emit a minimal IconifyJSON containing only those icons. Saves ~3 MB in the
+ * client bundle vs. shipping the full 7000+ icon collection.
+ *
+ * Dynamic icons (from CMS data, conditional names) cannot be detected
+ * statically — list them under EXTRA_ICONS below. Anything missing falls
+ * through to the iconify API at runtime, which adds a network roundtrip but
+ * does not break.
+ *
+ * Run via `npm run generate:icons`. Hooked into `prebuild`.
+ */
+
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const ROOT = path.resolve(__dirname, '..');
+const SRC_DIR = path.join(ROOT, 'src');
+const ICONS_JSON = path.join(ROOT, 'node_modules', '@iconify-json', 'mdi', 'icons.json');
+const OUT_FILE = path.join(ROOT, 'src', 'lib', 'iconify-mdi-subset.generated.json');
+
+/**
+ * Icons that appear via dynamic bindings (CMS data, conditional expressions)
+ * and would otherwise miss the static scan. Add new ones here when editors
+ * pick icons that appear blank — better than shipping the full collection.
+ */
+const EXTRA_ICONS = [
+  // PostActions: dynamic share/copy state
+  'share-variant-outline',
+  'link-variant',
+  // Search: file-type fallback
+  'file-outline',
+  // Common social icons editors pick (Header.svelte: social.icon)
+  'facebook',
+  'instagram',
+  'twitter',
+  'youtube',
+  'linkedin',
+  'mastodon',
+  'github',
+  'email',
+  'email-outline',
+  'phone',
+  'whatsapp',
+  'telegram',
+  // Common file-type icons (FilesBlock: f.iconName)
+  'file-pdf-box',
+  'file-word-box',
+  'file-excel-box',
+  'file-image',
+  'file-video',
+  'file-music',
+  // Tag/link/banner fallbacks (LinkListBlock, Tags, DeadlineBannerBlock)
+  'link',
+  'tag-outline',
+  'flag-outline',
+  'information-outline',
+];
+
+const STATIC_PATTERN = /icon="mdi:([a-z0-9-]+)"/g;
+
+function walk(dir) {
+  const out = [];
+  for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
+    if (entry.name === 'node_modules' || entry.name.startsWith('.')) continue;
+    const full = path.join(dir, entry.name);
+    if (entry.isDirectory()) {
+      out.push(...walk(full));
+    } else if (/\.(svelte|ts|tsx|js|mjs)$/.test(entry.name)) {
+      out.push(full);
+    }
+  }
+  return out;
+}
+
+function scanStatic() {
+  const found = new Set();
+  for (const file of walk(SRC_DIR)) {
+    const content = fs.readFileSync(file, 'utf8');
+    let m;
+    while ((m = STATIC_PATTERN.exec(content)) !== null) {
+      found.add(m[1]);
+    }
+  }
+  return found;
+}
+
+function main() {
+  if (!fs.existsSync(ICONS_JSON)) {
+    console.error(
+      `[generate-icons] missing ${ICONS_JSON} — run \`npm install\` first.`,
+    );
+    process.exit(1);
+  }
+  const collection = JSON.parse(fs.readFileSync(ICONS_JSON, 'utf8'));
+  const wanted = new Set([...scanStatic(), ...EXTRA_ICONS]);
+
+  const icons = {};
+  const aliases = {};
+  const missing = [];
+
+  for (const name of wanted) {
+    if (collection.icons[name]) {
+      icons[name] = collection.icons[name];
+    } else if (collection.aliases?.[name]) {
+      aliases[name] = collection.aliases[name];
+      const parent = collection.aliases[name].parent;
+      if (parent && collection.icons[parent] && !icons[parent]) {
+        icons[parent] = collection.icons[parent];
+      }
+    } else {
+      missing.push(name);
+    }
+  }
+
+  const subset = {
+    prefix: collection.prefix,
+    width: collection.width,
+    height: collection.height,
+    icons,
+    ...(Object.keys(aliases).length ? { aliases } : {}),
+  };
+
+  fs.writeFileSync(OUT_FILE, JSON.stringify(subset, null, 2) + '\n');
+
+  const sizeBefore = fs.statSync(ICONS_JSON).size;
+  const sizeAfter = fs.statSync(OUT_FILE).size;
+  console.log(
+    `[generate-icons] ${Object.keys(icons).length} icons + ${Object.keys(aliases).length} aliases → ${path.relative(ROOT, OUT_FILE)}`,
+  );
+  console.log(
+    `[generate-icons] ${(sizeBefore / 1024 / 1024).toFixed(2)} MB → ${(sizeAfter / 1024).toFixed(1)} KB (${((1 - sizeAfter / sizeBefore) * 100).toFixed(1)}% smaller)`,
+  );
+  if (missing.length) {
+    console.warn(
+      `[generate-icons] ${missing.length} icon(s) not found in MDI: ${missing.join(', ')}`,
+    );
+  }
+}
+
+main();