[ChrisPaulBennett]

Fix flake8-bugbear B045 lint failures

flake8-bugbear 26.10.27 (released 2026-10-27) added rule B045:
"Loop control variable overrides a variable in an enclosing loop".
This is currently failing the lint job on all PRs against 8.7.x:

./cylc/flow/data_store_mgr.py:809:21: B045 Loop control variable key overrides a variable in an enclosing loop.
./cylc/flow/id_cli.py:516:23: B045 Loop control variable tokens overrides a variable in an enclosing loop.

The inner loop variables have been renamed:

• data_store_mgr.py: key -> meta_key (family metadata loop).
• id_cli.py: tokens -> expanded_tokens (workflow pattern expansion).

Check List

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Applied any dependency changes to both setup.cfg (and conda-environment.yml if present).
• Tests are included (or explain why tests are not needed).
• Changelog entry included if this is a change that can affect users
• Cylc-Doc pull request opened if required at cylc/cylc-doc/pull/XXXX.
• If this is a bug fix, PR should be raised against the relevant ?.?.x branch.