refactor: rename package from mytoolkit to bin

- Move all source files from mytoolkit/ to bin/
- Update entry point and build config in pyproject.toml
- Add pillow and pypdf dependencies
- Update README and .gitignore paths
- Remove unused subprocess import in pdf.py
- Clean up duplicate imports in pdf merge command

README.md

@@ -97,7 +97,7 @@ mytoolkit env init                      # Print shell init snippet
 
 ## Configuration
 
-All settings are stored in `mytoolkit/config.json`:
+All settings are stored in `bin/config.json`:
 - `paths`: Quick navigation paths
 - `ssh_hosts`: SSH connection settings
 - `git_proxies`: Git proxy URLs
@@ -114,7 +114,7 @@ The repository includes `config.json.example` as a template.
 
 1. Copy the example config:
    ```bash
-   cp mytoolkit/config.json.example mytoolkit/config.json
+   cp bin/config.json.example bin/config.json
    ```
 
 2. Edit with your actual API keys: