fix(queue): restore background processing refactor lost in Phase 1 merge

[jakejackson1]

Summary

Phase 2 of the hot-patch ↔ development reconciliation. Phase 1 (#1655) merged hot-patch's bootstrap-level queue wiring (`GF_Background_Process` loader, queue-toggle cleanup hook, 4-arg `Controller_Pdf_Queue` construction) but the auto-merge took dev's copies of `Controller_Pdf_Queue`, `Queue_Callbacks`, and `Test_Controller_Pdf_Queue` — leaving the controller's constructor silently dropping its `Helper_Form` dependency and discarding the substantive changes from four hot-patch commits.

This commit re-applies those four commits' intent on top of dev's queue baseline:

Commit	What it brought back
`dc772da0`	GF 2.9.7/2.9.8 background-processing library compatibility (mostly already merged via bootstrap.php; `gfpdf_override_pdf_bypass=false` wrapper restored to `Queue_Callbacks::create_pdf`)
`8a7914dd`	Convert mini-queues to individual queue items; drop `'unrecoverable' => true` so one failure doesn't block other PDFs/notifications
`389ae6ce`	Queue cleanup on toggle (already landed in Phase 1 via `gfpdf_settings_sanitize` hook in bootstrap.php)
`3fe1c1e7`	Use the correct entry on resend; dedupe identical PDFs. Adds `Helper_Form` to `Controller_Pdf_Queue`, groups async notifications by `[formId][entryId]`, fans out resend over each pair, looks up form/entry fresh from the DB

`Helper_Pdf_Queue.php` is identical between dev and hot-patch already (retry budget = 1), so no changes there.

Dev's intent preserved

• `get_current_user_id()` is carried as an arg to `Queue_Callbacks::create_pdf` / `send_notification` so dev's `{user}` merge-tag masquerade keeps working when queues run later.
• `queue_cleanup_task()` + `Queue_Callbacks::cleanup_pdfs()` stay deprecated per dev's 6.12 caching-layer + hourly WP-Cron auto-purge direction. The cleanup queue entries hot-patch's controller used to push are no longer scheduled, and the tests assert the reduced queue size.

Test plan

• `composer phpcs:lint` — clean
• `yarn lint:js` — clean
• `yarn test:php` — 1119 tests, 4088 assertions, 8 skipped, 0 failures
• `yarn test:php --filter Test_Controller_Pdf_Queue` — 9 tests, 34 assertions
• CI: PHPUnit (`run-tests` label applied)
• CI: Coding standards
• CI: Playwright e2e

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.85%. Comparing base (a88359f) to head (46f8500).
⚠️ Report is 3 commits behind head on development.

Additional details and impacted files

@@             Coverage Diff              @@
##           development    #1656   +/-   ##
============================================
  Coverage        92.85%   92.85%           
============================================
  Files               58       58           
  Lines             1511     1511           
  Branches           419      419           
============================================
  Hits              1403     1403           
  Misses             103      103           
  Partials             5        5           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.