Remove git.renameBranch RPC and harden branch rename args

- remove `git.renameBranch` from WS/contracts/native API surface and update server/web tests
- use `git branch -m -- ...` in GitCore to safely separate branch rename arguments
0df68cc73eJulius Marminge committed on 3/1/2026, 6:35:09 AMparent61e1bab
9 files changedLine totals unavailable