ci(installer): cover all greenfield execution arms

docs/PRD.md

@@ -1393,14 +1393,14 @@ A from-zero install can report success while leaving the target host unusable be
 12. The expected-RED comparator SHALL validate the complete manifest before selecting a case: exact case population, one exit and P0–P9 disposition per case, pinned require/forbid classes, and no malformed, duplicate, or unknown rows.
 13. The published installer contract SHALL reject failed fetches, HTTP-success empty bodies, and digest mismatch, then execute the exact digest-verified body. The remote CI arm SHALL enumerate every payload-acquisition path and report a bound/found denominator. It SHALL bind both the installer body and the downstream stack framework/source it consumes to the same immutable CI commit, while retaining `--next` as the lane selector. Source resolution/acquisition SHALL fail closed, and the arm SHALL verify the realised source commit and archive digest after installation. Any out-of-scope unpinned sibling SHALL be named and counted rather than silently included in a broader pinning claim. `ASSUMPTION:` the configured repository's authenticated exact-commit endpoint is trusted to map that commit ID to the returned archive bytes; independent signed provenance/authenticity against repository or TLS trust-root compromise remains excluded by canonical greenfield-install PRD v2 §3.
 14. Phase diagnostics SHALL be redacted before terminal or durable-log output. A seeded positive-control canary SHALL remain absent from observed argv, output, command logs, npm configuration, generated files, and shell history.
-15. The CI fixture SHALL publish pipeline-level execution coverage for the unconditional case set derived from the expected-RED manifest. Per-case success markers SHALL be run-scoped and written only after that case's verifier passes. A final step SHALL depend on the complete fixture matrix, run after prior success or failure, emit `cases_defined=N cases_executed=M`, and fail unless the expected and executed case-name sets are exactly equal; missing, unexpected, stale, or newly added unexecuted cases SHALL fail closed.
+15. The CI fixture SHALL publish pipeline-level execution coverage for both the unconditional case set derived from the expected-RED manifest and the explicitly declared required pipeline-arm set, including the immutable remote-installer contract. Per-case and per-arm success markers SHALL be run-scoped, stored beneath an existing checkout-archive exclusion, and written only after that arm's verifier passes. A final step SHALL depend on the complete fixture matrix, run after prior success or failure, emit both `cases_defined=N cases_executed=M` and `arms_defined=N arms_executed=M`, and fail unless both expected/executed name sets are exactly equal; missing, unexpected, stale, newly added unexecuted, or checkout-contaminating state SHALL fail closed.
 
 ### C1 acceptance criteria
 
 1. The pre-C1 from-zero matrix records both discriminating controls: with `git` absent, the legacy installer still exits zero while P1 fails and skill sync degrades; with `git` present, P1 passes and the observed sync store/runtime links are 101/101. The C1 installer must fail at P1 before mutation when `git` is absent.
 2. The discriminating P3 row passes: the binary exists at the expected absolute path and reports exactly the resolved `next` lane version, while P4, P5, and P8 fail.
 3. The `--check` mutation negative control proves host fingerprints are byte-identical before and after observation.
-4. Woodpecker executes and validates the expected RED fixture plus the immutable remote-installer contract; its pipeline-level case-coverage gate reports exact manifest-derived set equality and a skipped-arm control proves non-execution is red. C1 does not repair P4/P5/P8 or activate #869.
+4. Woodpecker executes and validates the expected RED fixture plus the immutable remote-installer contract; its pipeline-level coverage gate reports exact equality for the manifest-derived case set and the declared arm set, while skipped-case and skipped-remote-arm controls prove non-execution is red. C1 does not repair P4/P5/P8 or activate #869.
 5. Negative controls prove manifest shrink/duplicates/unknown rows fail, unsafe P0/P3/P4/P5 contexts fail, the P2–P8 fault seam enters real actions rather than synthetic writes, empty/mismatched fetched bodies fail, and a deliberately emitted secret canary is redacted from every persisted/output population.
 
 ### Explicit exclusions and dependencies