docs(pipeline): align delivery contracts and verification requirements

openspec/changes/telecom-cdr-pipeline/specs/verification/spec.md

@@ -13,7 +13,7 @@ The test suite SHALL provide a script that generates synthetic CDR traffic to ex
 
 #### Scenario: Missing required field validation
 - **WHEN** the generator sends 20 records missing `caller_num`
-- **THEN** all 20 records are rejected by the API with HTTP 400 or routed to DLQ with `missing_required_field`
+- **THEN** all 20 records are rejected by the API with HTTP 400; 20 additional direct Kafka injections verify DLQ `missing_required_field`
 
 #### Scenario: Malformed JSON validation
 - **WHEN** the generator sends 10 invalid JSON payloads
@@ -46,3 +46,10 @@ The test script SHALL inspect ClickHouse, the DLQ, and API metrics after test ex
   - Records in DLQ
   - API 400 errors
   - Duplicate `raw_id`s resolved
+
+### Requirement: Independent durable evidence
+Verification SHALL inspect actual run-correlated DLQ envelopes and FINAL ClickHouse rows instead of inferring delivery from counters.
+
+#### Scenario: Full assessment run
+- **WHEN** 1570 HTTP requests and 30 direct Kafka fault injections finish
+- **THEN** verify 1540 HTTP acknowledgements, 30 structured HTTP rejections, 1500 unique stored rows, 50 actual DLQ records, correct transformations and metrics, and a 500-record burst under five seconds; unavailable evidence is failure