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.

backend/tests/fixtures/co_medicaid_837p.txt

@@ -17,7 +17,7 @@ NM1*IL*1*Balliache*Marianela****MI*P060946~
 N3*1811 PAVILION DR APT 303~
 N4*Montrose*CO*814016072~
 DMG*D8*19590223*F~
-NM1*PR*2*COHCPF*****PI*SKCO0~
+NM1*PR*2*CO_TXIX*****PI*CO_TXIX~
 CLM*t991102984o1c1d*85.40***12:B:1*Y*A*Y*Y~
 REF*G1*3173~
 HI*ABK:R69~
@@ -35,7 +35,7 @@ NM1*IL*1*Barella*Victoria****MI*H582447~
 N3*1900 Kellie DR~
 N4*Montrose*CO*814019524~
 DMG*D8*19570727*F~
-NM1*PR*2*COHCPF*****PI*SKCO0~
+NM1*PR*2*CO_TXIX*****PI*CO_TXIX~
 CLM*t991102984o1c2d*155.76***12:B:1*Y*A*Y*Y~
 REF*G1*3173~
 HI*ABK:R69~

backend/tests/fixtures/co_medicaid_837p_with_renderer.txt

@@ -17,7 +17,7 @@ NM1*IL*1*Balliache*Marianela****MI*P060946~
 N3*1811 PAVILION DR APT 303~
 N4*Montrose*CO*814016072~
 DMG*D8*19590223*F~
-NM1*PR*2*COHCPF*****PI*SKCO0~
+NM1*PR*2*CO_TXIX*****PI*CO_TXIX~
 CLM*t991102984o1c1d*85.40***12:B:1*Y*A*Y*Y~
 REF*G1*3173~
 HI*ABK:R69~
@@ -36,7 +36,7 @@ NM1*IL*1*Barella*Victoria****MI*H582447~
 N3*1900 Kellie DR~
 N4*Montrose*CO*814019524~
 DMG*D8*19570727*F~
-NM1*PR*2*COHCPF*****PI*SKCO0~
+NM1*PR*2*CO_TXIX*****PI*CO_TXIX~
 CLM*t991102984o1c2d*155.76***12:B:1*Y*A*Y*Y~
 REF*G1*3173~
 HI*ABK:R69~

backend/tests/fixtures/minimal_837p.txt

@@ -17,7 +17,7 @@ NM1*IL*1*Doe*John****MI*ABC123~
 N3*456 Member St~
 N4*Denver*CO*80203~
 DMG*D8*19800101*M~
-NM1*PR*2*COHCPF*****PI*SKCO0~
+NM1*PR*2*CO_TXIX*****PI*CO_TXIX~
 CLM*CLM001*100.00***12:B:1*Y*A*Y*Y~
 REF*G1*PA123~
 HI*ABK:Z00~