fix(source-control): externalize hardcoded bot logins + branch-to-issue grammar

[kyle-sexton]

Two-lane posture fixes (batched, one bump).

• W1 babysit_classify.py:113 DEPENDENCY_MANAGER_LOGINS frozenset — make configurable (mirror the existing babysit_review_bot_logins arg-threading) so non-dependabot/renovate dep bots keep hold-merge protection.
• W2 parse-branch-issue.sh:22 hardcoded <type>/<N>- grammar + numeric tracker — configurable grammar (fails safe today, but no override for Jira-key repos). Independent.

Part of #912. Contract + design in #912 — do not diverge.