[tool-slash-command] Git URL with #subdirectory= fragment not parsed correctly

Summary

The tool-slash-command module does not correctly parse git URLs that include a #subdirectory= fragment in the config.commands list.

Reproduction

In a bundle's behavior YAML:

tools:
  - module: tool-slash-command
    source: git+https://github.com/microsoft/amplifier-module-tool-slash-command@main
    config:
      commands:
        - git+https://github.com/microsoft/amplifier-bundle-issues@main#subdirectory=commands



Expected Behavior

The module should:

1 Parse git+https://github.com/microsoft/amplifier-bundle-issues@main as the repo URL
2 Extract commands from the #subdirectory= fragment
3 Clone the repo and look for commands in the commands/ subdirectory


Actual Behavior

The module treats main#subdirectory=commands as a branch name:


warning: Could not find remote branch main#subdirectory=commands to clone.
fatal: Remote branch main#subdirectory=commands not found in upstream origin



Impact

Bundles cannot ship slash commands in a subdirectory and have them automatically discovered. Users must manually copy commands to
~/.amplifier/commands/ as a workaround.


Suggested Fix

Parse the git URL to extract the #subdirectory= fragment before passing to git clone, similar to how uv and other tools handle this pattern.

Start in the tool-slash-command module at the config.commands parsing and git clone flow, using the behavior YAML reproduction from the issue. Verify that the repository URL stops before #subdirectory=, the fragment identifies commands/, and command discovery succeeds from that subdirectory; done means the listed bundle loads its slash commands without treating the fragment as part of the branch name.