[FEATURE] Allow specifying a specific branch when adding a marketplace

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Sometimes plugins maintained in GitHub repositories store the plugin in separate branches (e.g., the default branch holds the source code, and after compilation, the final output is published to a dedicated branch).

Proposed Solution

When adding a plugin via /plugin -> Add marketplace, it should be possible to optionally specify a specific branch.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_