Migrate the scenario subsystem and mutation-falsification harness to data-connectors before retiring pdpp's connector copy

[tnunamak]

What

Track migration of pdpp's scenario subsystem, scenario CLIs, and mutation-falsification harness to data-connectors before retiring pdpp's packages/polyfill-connectors copy. The harness lives under root scripts/, outside that package. Connector source ownership and the server/console move have landed; the September 5 audit confirmed production running a data-connect build with a data-connectors package. That audit did not establish completion of the whole reorg: consumer CI, live-branch/main reconciliation, documentation, and deferred required-check enforcement remain open.

Inventory to migrate or account for

Scenario subsystem (pdpp main, absent from data-connectors main)

• packages/polyfill-connectors/src/scenario/ — the complete tree: claims, isolation mechanism and its tests, recording, replay, format/validation, HAR, preload, and wire-registry code.
• packages/polyfill-connectors/bin/scenario-verify*.ts, scenario-record.ts, scenario-cli.test.ts, scenario-fidelity.test.ts, scenario-record-har.test.ts.

pdpp #274 (head 3a490c1de)
Six-file repair containing changes addressing the older external-review findings; final acceptance requires re-review. Files: .github/workflows/polyfill-connectors.yml, bin/scenario-verify.ts, bin/scenario-verify-strict.test.ts, src/scenario/claims.ts, src/scenario/isolation.ts, src/scenario/isolation-mechanism.test.ts. The isolation boundary is not certified closed: the strong replay claim stays withheld and its proof obligations stay tracked.

pdpp #263 (head 62473d87b), all 23 files

• 18 files under scripts/mutation-falsification/
• scripts/test-migration/mutation-oracle.ts
• test-accounting.manifest.json
• .gitignore
• openspec/changes/add-mutation-falsification-evidence/{DECISION-MEMO.md,tasks.md} — preserve the existing proposal/design context in that directory.

Migration obligations, not files that may silently disappear: scripts/test-accounting/authority.ts and its dependency closure, complete-suite/profile semantics, and packages/polyfill-connectors/connectors/groupme/incremental-frontier.test.ts. #263's recorded outcome is NARROW: the real GroupMe batch run and triage were incomplete, not passed.

Why not port now

A direct copy is incomplete: data-connectors lacks the scenario subsystem and pdpp's accounting/migration infrastructure. Migration needs an explicit destination interface and preserved evidence semantics, or an independently reviewed replacement. Decision (owner, 2026-09-06): #263 and #274 merge in pdpp after re-review; this issue tracks their migration together with the subsystem.

Done when

• Destination-native commands and CI in data-connectors run the scenario subsystem, scenario CLIs, and the mutation harness (or an independently reviewed replacement) with equivalent regression and falsifiability coverage, validated on behavior and evidence, not documentation alone.
• Every dependency, fixture, manifest entry, workflow, and OpenSpec obligation above has an explicit disposition.
• A rehearsal proves no remaining pdpp consumer needs the deleted package. Migration is verified before deletion; the deletion itself needs a separate exact-head review and sign-off. chore(move-b): remove the reference implementation, now canonical in data-connect #284 is precedent, not proof.
• data-connectors README no longer says pdpp's copy "still runs the product". That claim was already stale at the audit and can be fixed now, independent of migration.

Source: local September 5 audit ALIGNMENT-0905.md §C1–C2 (gpt-6-astra).

[tnunamak]

Owner direction (2026-09-06): this issue is the umbrella, not the deliverable. The work ships as mergeable data-connectors PRs: (1) port of the scenario subsystem plus pdpp #274, branch port/scenario-274; (2) port of pdpp #263 with the accounting infrastructure it needs. pdpp #274 and #263 stay open until each port merges, then close as superseded with links here.