Add SVN branch selection support alongside Git branch utilities

[beNative]

Summary

• allow repository cards and the branch selection modal to surface SVN branches with the same dropdown and search experience as Git
• add shared branch-formatting helpers and update the renderer to pass VCS-aware branch data to the UI
• update the IPC list-branches and checkout-branch handlers so both Git and SVN repositories are supported by the renderer API

Testing

• npx tsc --noEmit (fails: existing type errors in RepoFormModal icon definitions and missing Vite typings)

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https://chatgpt.com/codex/tasks/task_e_68e3c2359d7c83328ec448a3dfe41544