feat: add claudeArgs input for direct CLI argument passing

- Add claude_args input to both action.yml files
- Implement shell-style argument parsing with quote handling
- Pass arguments directly to Claude CLI for maximum flexibility
- Add comprehensive tests for argument parsing
- Log custom arguments for debugging

Users can now pass any Claude CLI arguments directly:
  claude_args: '--max-turns 3 --mcp-config /path/to/config.json'

This provides power users full control over Claude's behavior without
waiting for specific inputs to be added to the action.

base-action/action.yml

@@ -61,6 +61,10 @@ inputs:
     description: "Timeout in minutes for Claude Code execution"
     required: false
     default: "10"
+  claude_args:
+    description: "Additional arguments to pass directly to Claude CLI (e.g., '--max-turns 3 --mcp-config /path/to/config.json')"
+    required: false
+    default: ""
   experimental_slash_commands_dir:
     description: "Experimental: Directory containing slash command files to install"
     required: false