ticket: site metadata header + scannable Albanian ticket; widen barcode

- site_config gains optional park identity (park_name, operator_name, nius,
  address, phone, email); additive Drizzle migration 0001. GET/PUT
  /api/site-config read/write the full config (PUT partial patch, admin only);
  SiteSettings + SetupWizard expose the fields.
- renderTicket() prints an Albanian header sourced from site_config, the
  all-numeric 13-digit ticket id (12 random + Luhn) as Code128, large digits,
  and a lost-ticket footer. CP852 codepage so ë/ç render.
- Widen the Code128 module width 2->3 and height 80->100 dots so the
  short-range "Simple" QR/barcode reader decodes reliably (was barely reading
  at module width 2 on the 80mm head).

See wiki/concepts/site-metadata.md and ticket-encoding.md.

apps/server/src/signer.ts

@@ -58,3 +58,30 @@ export function buildSigner(log?: { warn: (msg: string) => void }): Signer {
     "event signing: no signing key. Set EVENT_SIGNING_KEY (>=16 chars) for the append-only event chain.",
   );
 }
+
+/**
+ * Resolve the signer that can VERIFY an existing event, by its stored `keyId`.
+ * Appends always use the one signer from buildSigner(), but a chain can contain
+ * events signed under different keys across a rotation (e.g. the JWT_SECRET
+ * fallback before a dedicated EVENT_SIGNING_KEY was set, or an ATECC608 swap).
+ * Each event stores its own `keyId`, so verifyChain() must check each row against
+ * the key that produced it — not the current append-signer. Returns undefined for
+ * an unknown keyId (the key is gone / not configured), which verifyChain surfaces
+ * as a distinct failure rather than a false "tampered" alarm.
+ *
+ * TODO(atecc608): add an "atecc608-slotN" case returning a public-key verifier.
+ */
+export function buildVerifier(keyId: string): Signer | undefined {
+  switch (keyId) {
+    case "sw-hmac-v2": {
+      const k = process.env.EVENT_SIGNING_KEY;
+      return k && k.length >= 16 ? new SoftwareSigner(k, "sw-hmac-v2") : undefined;
+    }
+    case "sw-hmac-jwtfallback": {
+      const k = process.env.JWT_SECRET;
+      return k && k.length >= 16 ? new SoftwareSigner(k, "sw-hmac-jwtfallback") : undefined;
+    }
+    default:
+      return undefined;
+  }
+}