feat(sp10): 277CA parser + Payer-Rejected Inbox lane

- Add cyclone.parsers.models_277ca + parse_277ca (X12 005010X214)
  - Per-Patient HL ClaimStatus with REF*1K (PCN), REF*EJ (tax ID),
    STC category code, amount, service date
  - STC classifier: A1-A3 accepted, A4/A6/A7 rejected, A8/A9 pended,
    P1-P5 paid, anything else unknown
  - Multiple STCs per Patient HL: last wins (canonical pattern for
    'first pended, then paid' acknowledgments)
  - Subscriber-level STCs surface in unscoped_statuses
- Add apply_277ca_rejections — stamps Claim.payer_rejected_* fields on
  matching rows (lookup by patient_control_number, mirrors 999 path)
- New /api/parse-277ca, /api/277ca-acks, /api/277ca-acks/{id} endpoints
- New two77ca_acks table + Two77caAck ORM model
- New Claim columns: payer_rejected_at, _reason, _status_code, _by_277ca_id
- New payer_rejected lane in /api/inbox/lanes (distinct from 999
  envelope rejected lane)
- New PayerConfig277CA block in config/payers.yaml + Pydantic model
- Migration 0008 bumps user_version to 8

Tests: 654 -> 688 (parser 22 + apply 6 + API 8 + config 6 + adjustments).
All 688 backend tests pass; 1 pre-existing skipped test class unaffected.

config/payers.yaml

@@ -42,3 +42,20 @@ payers:
           - "1811725341"
         expected_payer_health_plan_id: "7912900843"
         payer_name_pattern: "^CO_(TXIX|BHA)$"
+      "277CA":
+        # Per X12 005010X214. HCPF sends back 277CAs to acknowledge
+        # claims we submit. The parser matches each STC row against our
+        # 837 batch via REF*1K (cross-references CLM01 / patient_control_number).
+        #
+        # rejected_status_codes → claim ends up in the Inbox Payer-Rejected
+        # lane. Per HCPF's published STC code set, A4/A6/A7 are rejection,
+        # A8/A9 are pended, A1/A2/A3 are accepted, P1-P5 are paid.
+        rejected_status_codes: ["A4", "A6", "A7"]
+        pended_status_codes: ["A8", "A9"]
+        accepted_status_codes: ["A1", "A2", "A3"]
+        paid_status_codes: ["P1", "P2", "P3", "P4", "P5"]
+        # ST*01 transaction set identifier — HCPF uses "277CA" but the
+        # X12 005010X214 spec allows just "277". Both are accepted.
+        transaction_set_ids_allowed: ["277", "277CA"]
+        # Implementation guide version HCPF sends.
+        implementation_guide: "005010X214"