feat: Add grammar fetch and comparison tooling

- Add fetch_bind_grammar.py for MCP-based grammar file retrieval
- Add compare_bind_versions.py for version differences analysis
- Add process_mcp_result.py for handling base64-encoded MCP output
- Create upstream directory structure with fetching instructions
- Document grammar file locations and structure

scripts/process_mcp_result.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+"""
+Fetch BIND9 grammar files using Gitea MCP tools.
+This script must be run from an environment where MCP tools are available.
+"""
+
+import base64
+import json
+import sys
+from pathlib import Path
+
+# Files to fetch
+GRAMMAR_FILES = [
+    "options",
+    "forward.zoneopt",
+    "hint.zoneopt", 
+    "in-view.zoneopt",
+    "mirror.zoneopt",
+    "primary.zoneopt",
+    "redirect.zoneopt",
+    "secondary.zoneopt",
+    "static-stub.zoneopt",
+    "stub.zoneopt",
+    "delegation-only.zoneopt",
+    "rndc.grammar",
+    "parsegrammar.py",
+    "checkgrammar.py",
+]
+
+def save_file_from_mcp_result(result_json: dict, output_path: Path) -> bool:
+    """Save a file from MCP tool result JSON."""
+    try:
+        if 'Result' in result_json and 'content' in result_json['Result']:
+            content_b64 = result_json['Result']['content']
+            content = base64.b64decode(content_b64).decode('utf-8')
+            
+            output_path.parent.mkdir(parents=True, exist_ok=True)
+            with open(output_path, 'w', encoding='utf-8') as f:
+                f.write(content)
+            
+            return True
+        return False
+    except Exception as e:
+        print(f"Error saving {output_path}: {e}", file=sys.stderr)
+        return False
+
+def main():
+    """Process stdin JSON from MCP tool calls."""
+    print("Reading MCP tool results from stdin...")
+    
+    # Read all input
+    input_data = sys.stdin.read()
+    
+    try:
+        result = json.loads(input_data)
+        
+        # Determine output path from result metadata
+        if 'Result' in result and 'name' in result['Result']:
+            filename = result['Result']['name']
+            # Output path will be provided as command line argument
+            if len(sys.argv) > 1:
+                output_path = Path(sys.argv[1])
+                if save_file_from_mcp_result(result, output_path):
+                    print(f"✓ Saved: {output_path}")
+                    sys.exit(0)
+                else:
+                    print(f"✗ Failed to save: {output_path}", file=sys.stderr)
+                    sys.exit(1)
+        
+        print("✗ Could not determine output path", file=sys.stderr)
+        sys.exit(1)
+        
+    except json.JSONDecodeError as e:
+        print(f"✗ Invalid JSON input: {e}", file=sys.stderr)
+        sys.exit(1)
+
+if __name__ == "__main__":
+    main()