Fix S2B generator: preview letters pushed to translation then removed on generate

[Copilot]

S2B letters written in a language the child cannot read were pushed to the translation platform then immediately removed when using the Preview → Generate workflow.

Two compounding bugs:

• sbc_translation create() dispatched all new S2B letters (including Draft/preview) to the translation platform. Clicking "Preview" incorrectly queued the letter for translation.
• generate_letters_job found existing Draft letters via self.letter_ids and called letter.write(vals) — resetting state to "Received in the system" and silently pulling the letter out of the translation queue without re-dispatching.

The discrepancy between local and staging: local test data typically doesn't require translation (original_lang in language_ids), so letters took the create_commkit() path and the bug was never exposed. Staging with real data hits the translation path every time.

Changes

• sbc_translation/models/correspondence.py — skip Draft letters in create():

  # Draft letters (preview) are not ready to be dispatched yet
  if correspondence.state == "Draft":
      continue

• sbc_compassion/models/correspondence_s2b_generator.py — delete existing Draft letters before non-preview generation so they go through create(), which correctly handles translation/CommKit dispatch:

  if letter and not preview_mode:
      draft_letters = letter.filtered(lambda l: l.state == "Draft")
      draft_letters.unlink()
      letter -= draft_letters

[greptile-apps]

Confidence Score: 5/5

No blocking failure remains.

The exercised manual-validation and preview-to-final flows route final S2B letters through local translation when the field office does not support the source language.

T-Rex Logs

What T-Rex did

• • Ran a narrow Python harness to exercise the changed production method bodies of the parent revision and the current revision.
• • In the current revision, validation dispatches to a local translate path for an unsupported language, and after a preview the Draft was removed and replaced with a newly created final correspondence.
• • The fixes pinpointed in sbc_translation and related generator remove Draft creation from the flow and ensure validate() dispatch occurs after the parent validation.
• • The harness shows that final generation uses the normal create() path, preserving the dispatch route by removing the Draft preview.
• • The validation artifacts include the after-state executable and harness sources, confirming reproducibility of the test run.

_{Ran code and verified through T-Rex}

_{Reviews (3): Last reviewed commit: "T3404 Fix S2B generator: prevent preview..." | Re-trigger Greptile}