Migrate remaining hands-on scripts to RepoSmith v2 syntax

[jovnc]

Context

Several hands_on scripts still use the legacy download signature:

• def download(verbose: bool):

We should migrate all remaining scripts to RepoSmith v2 style:

• def download(rs: RepoSmith):

and replace legacy utility-wrapper patterns with RepoSmith v2 helpers where applicable.

Goal

Standardize all hands-on scripts on RepoSmith v2 syntax and usage to improve consistency, maintainability, and future compatibility.

Affected hands-on scripts

• hands_on/branch_rename.py
• hands_on/diff_files.py
• hands_on/fetch_merge.py
• hands_on/force_push.py
• hands_on/move_tags.py
• hands_on/populate_remote.py
• hands_on/remote_branch_delete.py
• hands_on/remote_branch_pull.py
• hands_on/remote_branch_push.py
• hands_on/remote_branch_rename.py
• hands_on/update_remote.py

Proposed migration work

• Update function signature from download(verbose: bool) to download(rs: RepoSmith).
• Use RepoSmith v2 helpers (rs.git, rs.files, rs.gh) instead of old wrapper/deprecated paths where possible.
• Keep behavior and final repository states unchanged from current exercise intent.

Acceptance criteria

• All affected scripts use download(rs: RepoSmith).
• No remaining old-signature hands-on downloads.
• Scripts execute successfully with expected end state.
• PRs should merge to reposmith-v2-migration branch instead of main branch

[jovnc]

Good example: https://github.com/git-mastery/exercises/blob/reposmith-v2-migration/hands_on/early_branch.py