feat(config): enable tool auto-execution by default by GCWing · Pull Request #138 · GCWing/BitFun

Set skip_tool_confirmation default to true in AIConfig so new users get auto-execute enabled out of the box; add a dedicated serde default fn so the value is also correct when the field is absent from an existing config file. Mark DeleteFileTool and FileWriteTool as not requiring permissions (needs_permissions to false), aligning with the auto-execute default.