Loki Mode v7.81.1

Fix: CI Shell-tests green (V2 python test runner-contract)

• The v7.81.0 worktree-bundle python test was registered in tests/run-all-tests.sh
  as run_test "..." "python3 <file>", but that runner invokes the entry via
  bash "$file" (it expects a single bash-executable file, not a command string),
  so it ran bash "python3 <file>" -> "No such file or directory" and the CI
  "Shell tests" job failed. local-ci passed because its run_check runs the entry
  as a shell command string (different contract), masking the bug.
• Fixed with a bash wrapper (tests/run-checkpoint-worktree-bundle-tests.sh) that
  exec's the python test, registered uniformly in both gates -- matching the
  existing python-test wrapper pattern. No product code changed; the test itself
  always passed (10/10). Full run-all-tests.sh now green (61 suites).