refactor: restructure mytoolkit with new subcommands and md-to-pdf improvements

- Add new subcommands: convert, preflight, server, templates, webpage
- Migrate config from bin/config.json to ~/.config/mytoolkit
- Fix expand_bookmarks to modify writer objects instead of reader
- Improve md_to_pdf with CJK bookmark support
- Update README and project metadata

bin/commands/env.py

@@ -2,7 +2,7 @@
 
 import click
 
-from bin.config import config
+from bin.config import CONFIG_PATH, config
 
 
 @click.group(name="env")
@@ -14,10 +14,12 @@ def env_cmd():
 @env_cmd.command("list")
 def env_list():
     """List all vars."""
+    click.echo(f"Storage: {CONFIG_PATH}")
     vars = config.get_all()
     if not vars:
         click.echo("No vars configured.")
         return
+    click.echo()
     for name, value in sorted(vars.items()):
         masked = "***" if any(x in name.lower() for x in ["key", "secret", "token", "pass"]) else value
         click.echo(f"{name:20} = {masked}")