docs: close R2 reproducibility checkpoint

docs/plans/2026-08-18-release-stabilization.md

@@ -420,8 +420,8 @@ checkpoint. Do not infer status from chat history.
 |---|---|---|---|---|
 | R0 | PLAN ACCEPTED; tracking/owner assignment pending | — | Audit complete at `15539a22`; user started R1 | Track plan+audit artifacts; assign R4 owner |
 | R1 | COMPLETE ON CAMPAIGN BRANCH; not yet merged | `0a934cf5` | 2026-08-18 checkpoint below; F-009/T-001 resolved and committed | Preserve while R2 runs; merge through the normal review path |
-| R2 | COMPLETE GATE CHECKPOINT ON CAMPAIGN BRANCH; broader reproducibility work remains | `2ac05486` | Checkpoint below; F-014 resolved, F-010/F-019 partially resolved | Choose locked restore/warning work or R3; merge through normal review |
-| R3 | NOT STARTED | — | T-002–T-018; F-015/F-021/F-022/F-030 | Wait for remaining R2 sequencing decision |
+| R2 | COMPLETE ON CAMPAIGN BRANCH; not yet merged | `2ac05486`, `c38f6b88` | Checkpoints below; F-014/F-019 resolved, F-010 machine-readable, supported .NET tool portion of F-004 resolved | Begin R3; merge through normal review |
+| R3 | NOT STARTED | — | T-002–T-018; F-015/F-021/F-022/F-030 | Begin complete test inventory, naming, skip, and value classification |
 | R4 | NOT STARTED; may run parallel | — | F-001/F-026/F-031/F-034 | Assign owner/legal provenance decision path |
 | R5 | NOT STARTED | — | F-002/F-003/F-006/F-007/F-011/F-020/F-027/F-029/F-032 | Wait for R2–R3 |
 | R6 | NOT STARTED | — | F-004/F-005/F-012/F-016/F-023/F-028 | Wait for R3/R5 |
@@ -571,6 +571,86 @@ the broader R2 reproducibility slice or R3 test-quality cleanup is complete.
 
 Rollback is `git revert 2ac05486`; do not rewrite branch history.
 
+### R2 reproducibility closeout — 2026-08-18
+
+**Working-tree base:** `b459e0cf0cab9241b0771d2ce6838083f2c84162`
+
+**Implementation commit:** `c38f6b88522750abc2e4acf1898ed566c5576e4a`
+on `codex/release-stabilization`; the closeout is durable on that campaign
+branch but is not yet merged to `main`.
+
+Repository policy and dependency graph:
+
+- `Directory.Build.props` is the common .NET 10, language, nullable, latest
+  analysis, warnings-as-errors, deterministic-build, and lock-file authority.
+- `Directory.Packages.props` centrally pins all 30 direct package versions.
+  All 89 `PackageReference` sites are versionless; no project-local version can
+  silently drift.
+- `NuGet.Config` clears machine fallback folders and package sources, then
+  declares only `nuget.org`.
+- Every supported project owns `packages.neutral.lock.json` (44 files). Every
+  shippable source project additionally owns `packages.win-x64.lock.json` and
+  `packages.linux-x64.lock.json` (14 of each; 72 graphs total). Conventional
+  `packages.lock.json` files are intentionally absent because NuGet gives that
+  filename precedence over `NuGetLockFilePath`, preventing adjacent neutral
+  and RID graphs.
+- `tools/update-package-locks.ps1` is the one intentional update path. The
+  release gate and the launcher's nested Bake publish use forced locked restore,
+  so stale `obj/` assets cannot hide a disagreement and a normal gate cannot
+  rewrite dependency resolution.
+
+Complete maintained build surface:
+
+- All 13 tracked .NET tools were repaired against package/owned interfaces,
+  documented in `tools/README.md`, and added to `AcDream.slnx`.
+- The gate now verifies that every `.csproj` under `src/`, `tests/`, and
+  `tools/` is a solution member, requires the expected lock graphs, and records
+  their hashes in the evidence bundle. The supported graph is 44 projects.
+- The older script/probe archive under F-004 is unchanged. Classifying that
+  historical material remains R6 work; the R2 change only makes the maintained
+  .NET tools truthful and reproducible.
+
+Warning cleanup and test-gate stability:
+
+- A clean complete recompilation originally exposed 26 warnings, all in test
+  and diagnostic code. Assertion-specific analyzers, nullable test doubles,
+  and nullable DAT probe boundaries were corrected without changing product
+  behavior.
+- The one known redundant historical Core theory input remains for R3 behind a
+  site-scoped `xUnit1025` suppression. The central policy still makes any new
+  duplicate row a build failure.
+- The launcher's seven editor-focus variants now execute in one Avalonia test
+  application session. This prevents the headless framework from attempting
+  compositor reinitialization on a non-owning thread. The suite passed 11
+  consecutive focused runs before the full gate. Aggregating seven theory rows
+  into one fact reduces the headline passed count by six; all seven variants
+  are still executed and asserted.
+- The launcher package-boundary test now verifies versionless project
+  references against the central version table rather than incorrectly
+  requiring inline versions.
+
+Reproducibility evidence:
+
+- Forced locked re-evaluation of all 44 neutral and all 28 RID graphs changed
+  zero lock hashes.
+- A locked restore into an empty global package cache, with `--no-cache`,
+  succeeded from the sole configured source. NuGet assets recorded no fallback
+  package folder.
+- A forced nested launcher-to-Bake publish selected the appropriate RID graph,
+  emitted the Bake executable, and changed zero lock hashes.
+- `pwsh ./tools/run-release-gate.ps1` ran on the clean exact commit
+  `c38f6b88522750abc2e4acf1898ed566c5576e4a`, SDK `10.0.300`, RID `win-x64`,
+  in 121.398 seconds. Restore was forced and locked; all 44 projects built with
+  0 warnings / 0 errors; all 12 test assemblies completed with 14,742 passed /
+  77 skipped / 0 failed. The gate recorded `WorktreeDirty: false`.
+
+No product source behavior changed in this closeout. The known duplicate theory
+row, classification of the 77 environment-dependent skips, test naming/value
+review, and stale public headline counts remain explicitly assigned to R3 and
+the later documentation-authority slice. R2 is complete on the campaign branch.
+
+Rollback is `git revert c38f6b88`; do not rewrite branch history.
+
 ## 18. Session start protocol
 
 Every implementation session begins by: