refactor: retire platforms source seam

[thymikee]

Summary

Retire the final src/platforms seam and move the remaining cross-family install-source tests to their root test owner.

Remove the obsolete R3 folder policy and dead affected-test routing. R13 remains the concrete package import owner, while a new all-file retirement gate prevents the old root from returning.

Update ADR 0019 and the dependency-graph findings to record the completed physical ownership boundary, Apple’s named facades, and the durable R13/R65 split.

Closes #2082

Validation

• Planted red: the terminal boundary test accepted a tracked file under src/platforms before the implementation.
• pnpm check:affected --run — all runnable checks passed after rebasing onto merged main.
• Focused policy/model suite: 82 tests passed.
• Vitest related: 2 files / 414 tests passed.
• Layering graph: 1,522 files, 0 value cycles, 0 spine backedges, and no platforms zone.
• Adversarial review and worker-diff reconciliation resolved a non-TypeScript fixture blind spot, stale path-ownership language, and missing Apple facade documentation.

[github-actions]

Size Report

Metric	Base	Current	Diff
JS raw	2.51 MB	2.51 MB	0 B
JS gzip	839.3 kB	839.3 kB	0 B
npm tarball	966.7 kB	966.7 kB	0 B
npm unpacked	3.35 MB	3.35 MB	0 B

npm unpacked components

Component	Base	Current	Diff
JS / dist source	2.66 MB	2.66 MB	0 B
Apple runner source/project	581.1 kB	581.1 kB	0 B
macOS helper source	54.8 kB	54.8 kB	0 B
Android helper artifacts	0 B	0 B	0 B
Other package files	45.6 kB	45.6 kB	0 B

Startup median (7 runs, lower is better):

Scenario	Base	Current	Diff
CLI --version	30.6 ms	30.3 ms	-0.3 ms
CLI --help	83.5 ms	84.1 ms	+0.7 ms

Top changed chunks: no changes in the largest emitted chunks.

Top changed packed files

No changed packed files.

[thymikee]

Reviewed exact head b6de3b6e77 as the stack child of #2118.

• P1 — the retirement gate misses an exact tracked src/platforms entry. git ls-files -- src/platforms can return the root path itself when it is a tracked file, symlink, or gitlink, but checkRetiredPlatformsZone only rejects strings beginning src/platforms/. Include file === 'src/platforms' and plant that exact-root case so the claimed terminal boundary is complete.
• P2 — ADR 0019 still contradicts the enforced Apple export surface. It says Apple exposes its root plus exactly ./runner, ./runner/client, and ./runner/test-host, while refactor: move Apple platform family into package #2118/R13 now enforce eighteen exports with many domain facades. Scope that sentence to the runner facet or point accurately to the complete R13 declaration.

Otherwise the empty old tree, moved cross-family tests, coverage pointer, stack base, and completed CI checks look good. The PR body’s retarget note is also stale; iOS smoke remains pending.

[thymikee]

Rechecked 95ab1df3ce: tree-identical to reviewed b6de3b6e77; both findings remain unchanged.

[thymikee]

Structural/code review is clear on exact head b2c9d5db2e7b363b248a58fd0e378037c36f3f50: it retires the final tracked src/platforms paths, rejects any future production/test/fixture file under that root, and preserves R13/R65 ownership without changing command identity or runtime behavior. The change is net-negative and no materially smaller safe design stood out.

I cannot mark it merge-ready because exact-head iOS Smoke is red (TEXT_INPUT_COMMIT_NOT_OBSERVED in seed email field). The diff does not touch that route, but the required check needs a successful rerun or documented disposition first.

[thymikee]

The failed iOS job was rerun against exact head b2c9d5d and is now green. The previously failing fixture-backed simulator E2E step passed, along with the remaining iOS smoke coverage. The stale CI blocker is cleared.

[thymikee]

Re-verified exact head b2c9d5db2e7b363b248a58fd0e378037c36f3f50: all checks are now green, including the rerun iOS Smoke. No code or readiness blocker remains. The structural review is unchanged—this safely retires the final src/platforms root while preserving R13/R65 ownership and public/runtime behavior. As the clean bottom of the #2123 → #2125 stack, it is ready for human review.

[github-actions]

PR Preview Action v1.8.1
Preview removed because the pull request was closed.
2026-08-29 11:11 UTC