Add source field support and Fabric import script

- Add ToolSource dataclass for attribution metadata (type, license, url, author, original_tool)
- Add source and version fields to Tool dataclass
- Update Tool.from_dict() and to_dict() to handle source field
- Display source attribution in TUI info panel
- Show [imported]/[forked] markers in cmdforge list
- Add import_fabric.py script to import Fabric patterns as CmdForge tools

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

src/cmdforge/cli/tool_commands.py

@@ -23,7 +23,14 @@ def cmd_list(args):
     for name in tools:
         tool = load_tool(name)
         if tool:
-            print(f"  {name}")
+            # Show source indicator for imported tools
+            source_marker = ""
+            if tool.source and tool.source.type == "imported":
+                source_marker = " [imported]"
+            elif tool.source and tool.source.type == "forked":
+                source_marker = " [forked]"
+
+            print(f"  {name}{source_marker}")
             print(f"    {tool.description or 'No description'}")
 
             # Show arguments