feat: Improve pr command and refix claude reviews

[ovitrif]

This PR:

1. Makes the /pr command flexible for multi-repo use by extracting the repo identifier dynamically
2. Adds library repo QA Notes guidance for repos without UI (Rust libraries, backends)
3. Updates the Claude Code review workflow to use the official code-review plugin
4. Adds related repositories section to the README
5. Auto-detects the default branch instead of hardcoding master

Description

The /pr command has been updated to work across different repository types. It now dynamically extracts the repo identifier from git remote, making it portable to any repo. For library repos (with bindings/ or Cargo.toml), it provides tailored QA Notes guidance focusing on testing and integration PRs.

The Claude Code review workflow has been simplified by switching to the official code-review plugin from the claude-code-plugins marketplace. Additional triggers (ready_for_review, reopened) have been added.

• The update was done by re-running /install-github-app using the latest version of Claude Code then borrowing the changes from the branch that the agent created automatically, and adjusting so we adopt their relevant changes while not dropping our adjustments.

The README now includes a Related Repositories section listing the ecosystem of repos that make up the Bitkit project.

Preview

N/A - tooling and documentation changes

QA Notes

1. /pr Command

   • Run /pr --dry in bitkit-android
   • Verify it correctly extracts repo as synonymdev/bitkit-android
   • Verify Preview section is included (template has ### Preview)

2. Code Review Workflow

   • The workflow uses the new code-review plugin
   • Triggers on: opened, synchronize, ready_for_review, reopened

3. README

   • Check Related Repositories section has correct links

[ovitrif]

@jvsena42 pushed again to fix bitkit-docker refs:
6d68694

[ovitrif]

Will open a PR for some migration fixes shortly after this one gets auto-merged, to verify that the claude reviews are working now.