feat(blocks): add typed personalization resolution

packages/blocks/src/schema.ts

@@ -92,8 +92,14 @@ export function safeUrl(
       if ((value === undefined || value === "") && options.optional) return { ok: true, value: "" };
       if (typeof value !== "string" || value.length > 4_096)
         return fail("schema.url", "Expected a bounded URL.", path);
+      const token = /^\{\{\s*[A-Za-z][A-Za-z0-9_.-]*(?:\|[^{}]*)?\s*\}\}$/;
+      if (token.test(value)) return { ok: true, value };
       try {
-        const parsed = new URL(value);
+        const templated = value.replace(
+          /\{\{\s*[A-Za-z][A-Za-z0-9_.-]*(?:\|[^{}]*)?\s*\}\}/g,
+          "variable",
+        );
+        const parsed = new URL(templated);
         return schemes.has(parsed.protocol.replace(/:$/, ""))
           ? { ok: true, value: parsed.href }
           : fail("schema.url.scheme", `URL scheme ${parsed.protocol} is not allowed.`, path);