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
82681606d0Julius Marminge committed on 3/2/2026, 4:06:21 AM· committed by Julius Marmingeparentc91b79b
9 files changedLine totals unavailable