feat(xattr): carry and apply symlink xattrs (protocol 2.29.0)

tests/test_config.c

@@ -2924,7 +2924,7 @@ static void golden_config_populate(Config* c) {
   array_list_add(c->filters, str_dup("- /sub/dir/"));
 }
 
-/* The pinned golden frame (protocol 2.28.0).  The values below are the only
+/* The pinned golden frame (protocol 2.29.0).  The values below are the only
  * thing that ties the generated table to the historical wire format; update
  * them ONLY with a PROTOCOL_VERSION bump and a documented reason.  The 2.24.0
  * delete-plan wave changed only the version string; 2.25.0 appended the
@@ -2933,10 +2933,13 @@ static void golden_config_populate(Config* c) {
  * appended the receiver-side delete-protection rule block (the STATUS_STATS
  * body also grew, but that is not part of this frame).  Track 5a appends the
  * FastSync-only verify_basis bool to the basis block WITHOUT a version bump
- * (project decision), so the frame grew by one int to 886 bytes.  The
- * byte-exact values are recomputed for the merged layout. */
+ * (project decision), so the frame grew by one int to 886 bytes.  The 2.29.0
+ * symlink-xattr wave changes only the version string: the config-frame layout
+ * is unchanged (use_xattrs already crosses the wire); the STATUS_SYMLINK frame
+ * body grows instead.  The byte-exact values are recomputed for the merged
+ * layout. */
 #define GOLDEN_WIRE_LEN 886
-#define GOLDEN_WIRE_HASH 5809509022716816757ULL
+#define GOLDEN_WIRE_HASH 17827864270611927842ULL
 
 static unsigned long long fnv1a_64(const unsigned char* buf, size_t len) {
   unsigned long long h = 1469598103934665603ULL;
@@ -3018,7 +3021,7 @@ static unsigned long long capture_wire_hash(const Config* cfg, size_t* out_len)
   return h;
 }
 
-/* Byte-for-byte wire compatibility guard (protocol 2.28.0).  The expected hash
+/* Byte-for-byte wire compatibility guard (protocol 2.29.0).  The expected hash
  * pins the pre-X-macro byte stream; the refactor MUST NOT change it. */
 static void test_config_wire_golden() {
   if (is_running_under_valgrind())