feat: add post-generation script to preserve buffer overflow fix

Created scripts/post-generate.sh that automatically re-applies the critical
buffer overflow fix to parser.h after tree-sitter generate runs. This fix
prevents undefined behavior in set_contains() when accessing an empty array.

The script is automatically executed after tree-sitter generate via the npm
generate script. Added generate:only for cases where post-processing should
be skipped.

scripts/post-generate.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+set -e
+
+echo "Running post-generation fixes..."
+
+# Apply critical safety fixes that get overwritten during generation
+echo "  - Applying critical safety fixes..."
+
+# Fix 1: Buffer overflow prevention in parser.h
+# The set_contains function needs a len==0 check to prevent accessing ranges[0]
+# This fix gets overwritten every time tree-sitter generate runs
+if ! grep -q "if (len == 0) return false;" src/tree_sitter/parser.h; then
+  # Insert the safety check right after the function opening
+  # Target: static inline bool set_contains(...) {
+  # Insert: if (len == 0) return false;
+  # Before: uint32_t index = 0;
+
+  # Use perl for cross-platform compatibility (macOS and Linux)
+  perl -i -pe '
+    BEGIN { $in_func = 0; $done = 0; }
+    if (/static inline bool set_contains/) { $in_func = 1; }
+    if ($in_func && /^\s+uint32_t index = 0;/ && !$done) {
+      print "  if (len == 0) return false;\n";
+      $done = 1;
+    }
+    if (/^}/ && $in_func) { $in_func = 0; }
+  ' src/tree_sitter/parser.h
+  echo "    ✓ Applied buffer overflow fix to parser.h"
+else
+  echo "    ✓ Buffer overflow fix already present"
+fi
+
+echo "Post-generation fixes complete!"