feat(sp33): cli resubmit-rejected-claims + fixture/test payer_id refresh

- Adds `cyclone resubmit-rejected-claims` to push corrected single-claim
  837 files to the Gainwell ToHPE SFTP dir. Idempotent (stat-then-skip by
  byte size). One persistent paramiko session per batch with
  reconnect-every=50 to dodge MOVEit's silent per-session file cap
  (~200 puts/session, no exception).
- Validates each file via `parse_837` before upload and rejects any
  whose payer_id is not `CO_TXIX` (catches a bad byte-fix early).
- Refreshes test fixtures (`minimal_837p.txt`, `co_medicaid_837p.txt`,
  `co_medicaid_837p_with_renderer.txt`) and the corresponding test
  assertions (`test_payer.py`, `test_payer_summary.py`,
  `test_co_medicaid_fixture.py`, `test_parse_837.py`) from the old
  `SKCO0`/`COHCPF` payer IDs to `CO_TXIX`, matching
  PayerConfig.co_medicaid() and the HCPF 837P Companion Guide.
- Adds `ingest/` to .gitignore — local scratch / production-data
  staging only.

.gitignore

@@ -38,3 +38,7 @@ claims_output/
 # Brainstorm session artifacts (visual companion mockups, events, server state).
 # Skills under .superpowers/skills/ are committed project-scoped guidance.
 .superpowers/brainstorm/
+
+# SP33+ scratch / production-data ingest. Generated artifacts live
+# here only — the source EDI sits under docs/prodfiles/.
+ingest/