* ci: fix merge-queue trigger gaps and add develop to CI branches

Default branch moved to develop; keep CI running on both develop and main.
Also close two merge-queue trigger mismatches surfaced during a workflow
trigger audit.

- ci/typecheck/unit-tests/ui-tests: add `develop` to push branches so
  post-merge runs happen on both develop and main.
- pr-tittle-check: add a `merge_group` trigger and guard the validate step
  with `if: github.event_name != 'merge_group'`. As a required check it was
  never reporting on the queue commit, leaving the merge queue stuck
  "waiting for status to be reported"; it now reports success without
  re-validating (the title can't change in the queue).
- linter (Frappe Linter): drop `if: github.event_name == 'pull_request'` so
  lint is enforced in the merge queue instead of being skipped (a skipped
  required check counts as green).
- linter (Vulnerable Dependency Check): restrict to pull_request plus a new
  weekly schedule, and keep it off merge_group/push so a freshly published
  CVE in the external advisory DB can't block a queued merge.
- ci: rename concurrency prefix main-buzz -> ci-buzz now that main is not the
  default branch (no functional effect).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013EYfuce7SdhQDyZNCRMaNa

* ci: trim verbose workflow comments

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013EYfuce7SdhQDyZNCRMaNa

---------

Co-authored-by: Claude <noreply@anthropic.com>
(cherry picked from commit 2e16e49)