feat: delete DOProvider.Apply v1 wrapper; release v1.4.0 (Phase 3)

[intel352]

Summary

Phase 3 of workflow#695 cascade closeout cleanup. Resolves Copilot's PR #123 finding about FinalizeApply-vs-Apply deferred-flush loop duplication.

Why minor (v1.4.0) not patch

Observable behavior change: DOProvider.Apply now returns ErrApplyV1Removed sentinel instead of v1-dispatch result. No real-world callers exist (verified via grep post-Phase-2.5 closeout); semver convention treats behavioral change as minor.

Design

Per docs/plans/2026-05-17-phase2.5-cleanup-bundle-design.md (in workflow repo): sentinel-error stub preserves interfaces.IaCProvider contract per ADR 0024. Clean deletion not viable without breaking interface for all 4 plugins simultaneously; interface segregation (split Apply off into LegacyApplier) deferred to separate workflow-side refactor design (followup tracking issue to be filed post-cascade).

Changes

• internal/provider.go: delete deferredUpdater interface + v1 wrapper body; add ErrApplyV1Removed sentinel; replace Apply body with stub returning sentinel
• internal/iacserver.go: relocate deferredUpdater named interface near FinalizeApply method (sole consumer)
• internal/provider_apply_stub_test.go (new): TestDOProvider_Apply_ReturnsRemovedError uses errors.Is for sentinel classification
• internal/deferred_test_helpers_test.go (new): helpers (minimalDBMock, fakeAppForDeferred, sequencedAppsForDeferred) relocated from deleted provider_deferred_test.go; consumed by iacserver_finalize_test.go (Phase 2.5 T8 regression)
• internal/provider_deferred_test.go DELETED: regression migrated to iacserver_finalize_test.go (Phase 2.5 T8)
• internal/provider_apply_test.go + internal/provider_test.go (team-lead-authorized scope extension): delete 11 pre-existing v1 Apply tests that exercise the now-deleted v1 wrapper. Equivalent coverage preserved at wfctlhelpers/apply*_test.go + internal/drivers/*_test.go + iacserver_finalize_test.go.
• plugin.json: version 1.3.0 → 1.4.0

Test plan

• go build ./... → clean
• go vet ./... → clean
• go test ./internal/ -run TestDOProvider_Apply_ReturnsRemovedError -v → PASS
• go test ./... -race -count=1 → 6 packages PASS race-clean
• Phase 2.5 regression preserved: TestDOIaCServer_FinalizeApply_FlushesDeferredUpdates + TestDOIaCServer_FinalizeApply_PreservesPerDriverErrorAttribution + TestDOIaCServer_Capabilities_DeclaresV2 — all PASS
• No orphan imports post-deletion (wfctlhelpers removed from provider.go)

Rollback

Revert PR. Restores v1.3.0 state (Apply v1 body + deferredUpdater in provider.go + provider_deferred_test.go + 11 v1 Apply tests). Cut v1.4.1 reverting whichever change broke. Per ADR 0024 hard-cutover discipline.

If real in-process embedder surfaces: cut v1.4.1 with deprecation warning instead of sentinel error.

[intel352]

iac-codemod refactor-apply report

Mode: dry-run
Sites: 1
Errors: 0

Missing action-switch — hand-port required

• internal/provider.go:241 DOProvider.Apply missing-action-switch
  • suggestion: Apply body has no switch action.Action dispatch — wfctlhelpers.ApplyPlan expects this loop+switch shape; hand-port required.

Full report (90-day retention) attached as workflow artifact.

[Copilot]

Pull request overview

This PR completes the Phase 3 cleanup by removing the legacy v1 DOProvider.Apply implementation and replacing it with a sentinel-error stub while keeping v2 deferred-update finalization on the typed IaC server path.

Changes:

• Bumps plugin metadata and release URLs to v1.4.0.
• Replaces DOProvider.Apply with ErrApplyV1Removed.
• Moves deferred-update test fixtures into a shared test helper file and removes v1 Apply tests.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
plugin.json	Updates plugin version and release asset URLs to v1.4.0.
internal/provider.go	Removes wfctlhelpers Apply wrapper and adds the v1-removed sentinel stub.
internal/iacserver.go	Relocates the deferredUpdater interface near FinalizeApply.
internal/provider_test.go	Removes legacy v1 Apply coverage and now-unused helpers/imports.
internal/provider_deferred_test.go	Deletes v1 deferred-flush Apply tests.
internal/provider_apply_test.go	Deletes legacy v1 Apply dispatch tests.
internal/provider_apply_stub_test.go	Adds sentinel-error coverage for the new Apply stub.
internal/deferred_test_helpers_test.go	Adds shared deferred-update fixtures for FinalizeApply tests.

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[intel352]

Copilot review acknowledgement

Both inline comments flag cross-repo doc-path references in test godocs (docs/plans/2026-05-17-phase2.5-cleanup-bundle.md). Path lives in workflow repo, not DO. Same advisory Minor internal code-reviewer raised at T5 quality review.

Defensible cross-repo provenance pattern: Phase 2.5 cascade (PR #123) used the same cross-repo design-doc breadcrumb in iacserver_finalize_test.go. The path is stable because design docs are LOCKED at scope-lock time (this one sha256 19b0c80e0620 per workflow repo). Removing or qualifying the path loses the audit trail for why the test exists.

Tracked + accepted by internal code-reviewer as advisory Minor (waivable). Per Phase 2.5 precedent, prefer cross-repo path with full provenance over symbol-only refs that lose the cascade context.

CI green; admin-merging.