feat(errors): per-status static error pages for nginx fallback

Adds prerendered, JS-less, self-contained error pages for nginx
error_page use — served directly from /var/www/errors/ when the
SvelteKit upstream is unreachable or any nginx-originated 4xx/5xx
fires (including the catch-all default_server for unknown hosts).

- /errors/[status] (DE default) + /errors/en/[status] (EN), each
  with a header language toggle linking absolute to bocken.org so
  the switch works even on unknown-host fallbacks.
- httpStatus param matcher restricts entries to 401/403/404/500/
  502/503/504; entries() drives prerender output.
- generate-error-quotes.ts looks up curated bilingual references
  in the existing allioli/drb TSV bibles at prebuild time and
  writes src/lib/data/errorQuotes.json.
- build-error-page.ts (postbuild) inlines all CSS, strips module
  preloads/scripts, rewrites the home-link to canonical https URL,
  and emits .html + .gz + .br per status under build/client/errors.
- deploy.sh syncs build/client/errors → /var/www/errors with
  http:http ownership for nginx access.

scripts/generate-error-quotes.ts

@@ -0,0 +1,60 @@
+/**
+ * Build-time generation of bilingual Bible quotes per HTTP error status.
+ *
+ * Looks up curated references in static/allioli.tsv (DE) + static/drb.tsv (EN)
+ * via the existing bible reference parser, then writes the resolved verses to
+ * src/lib/data/errorQuotes.json for the prerendered /errors/[status] pages.
+ *
+ *   - Add or change a status by editing REFS below.
+ *   - Refs use the abbreviations defined in the TSVs (e.g. Mt 7,7 / Mt 7:7).
+ *   - Fails the build if any reference cannot be resolved.
+ *
+ * Run: pnpm exec vite-node scripts/generate-error-quotes.ts
+ */
+import { mkdirSync, writeFileSync } from 'node:fs';
+import { dirname, resolve, join } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { lookupReference } from '../src/lib/server/bible';
+
+const HERE = dirname(fileURLToPath(import.meta.url));
+const ROOT = resolve(HERE, '..');
+const ALLIOLI = join(ROOT, 'static/allioli.tsv');
+const DRB = join(ROOT, 'static/drb.tsv');
+const OUT = join(ROOT, 'src/lib/data/errorQuotes.json');
+
+// Curated refs. Abbreviations must match the TSV's `abbreviation` column.
+const REFS: Record<number, { de: string; en: string }> = {
+  401: { de: 'Mt 7,7',     en: 'Mt 7:7' },
+  403: { de: 'Mt 7,14',    en: 'Mt 7:14' },
+  404: { de: 'Mt 7,8',     en: 'Mt 7:8' },
+  500: { de: '2Kor 4,7',   en: '2Cor 4:7' },
+  502: { de: '1Mo 11,9',   en: 'Gn 11:9' },
+  503: { de: 'Ps 37,7',    en: 'Ps 37:7' },
+  504: { de: 'Jes 40,31',  en: 'Is 40:31' }
+};
+
+type ResolvedQuote = { text: string; reference: string };
+
+function resolveOne(ref: string, tsv: string): ResolvedQuote {
+  const result = lookupReference(ref, tsv);
+  if (!result || result.verses.length === 0) {
+    throw new Error(`could not resolve reference "${ref}" in ${tsv}`);
+  }
+  // Range refs join verses with a space. Display reference reuses the
+  // original input so the UI keeps the canonical "Mt 7,7" / "Mt 7:7" form.
+  const text = result.verses.map((v) => v.text).join(' ');
+  return { text, reference: ref };
+}
+
+const out: Record<string, { de: ResolvedQuote; en: ResolvedQuote }> = {};
+for (const [status, refs] of Object.entries(REFS)) {
+  out[status] = {
+    de: resolveOne(refs.de, ALLIOLI),
+    en: resolveOne(refs.en, DRB)
+  };
+  console.log(`[error-quotes] ${status}: ${refs.de} / ${refs.en}`);
+}
+
+mkdirSync(dirname(OUT), { recursive: true });
+writeFileSync(OUT, JSON.stringify(out, null, 2) + '\n', 'utf8');
+console.log(`[error-quotes] wrote ${OUT.replace(ROOT + '/', '')} (${Object.keys(out).length} statuses)`);