fix: clarify prepare ios-runner timing overlap

[thymikee]

Summary

Closes #1046.

Adds machine-readable prepare timing guidance so agents do not add overlapping fields as wall-clock totals: legacy buildMs/connectMs/healthCheckMs stay in place, while timing.additiveParts and timing.containment explain the safe additive breakdown. Also mirrors the containment label in runner diagnostics and documents it in CLI help, typed client comments, and website command docs.

Touched files: 8.

Validation

Focused prepare/runner timing tests passed: pnpm exec vitest run src/daemon/handlers/tests/session.test.ts src/platforms/apple/core/tests/runner-command-retry.test.ts src/utils/tests/args.test.ts.

Static quick checks passed: pnpm check:quick. Formatter passed: pnpm format. Build passed: pnpm build.

Residual risk: pnpm check:unit was attempted after building dist. The first run reached smoke tests and failed because dist was missing before the build. After building, reruns hit broad unrelated timeout/mocked-tool failures across Android, Apple, archive, Metro, and upload tests, while the focused touched tests stayed green.

[github-actions]

PR Preview Action v1.8.1
Preview removed because the pull request was closed.
2026-07-03 11:06 UTC

[github-actions]

Size Report

Metric	Base	Current	Diff
JS raw	1.5 MB	1.5 MB	+758 B
JS gzip	483.6 kB	484.0 kB	+345 B
npm tarball	585.4 kB	585.9 kB	+446 B
npm unpacked	2.1 MB	2.1 MB	+949 B

Startup median (7 runs, lower is better):

Scenario	Base	Current	Diff
CLI --version	27.5 ms	27.6 ms	+0.1 ms
CLI --help	48.4 ms	48.4 ms	+0.1 ms

Top changed chunks:

Chunk	Raw diff	Gzip diff
dist/src/session.js	+501 B	+233 B
dist/src/2948.js	+160 B	+79 B
dist/src/9722.js	+97 B	+33 B

[thymikee]

Review: LGTM. The additive design is exactly right: legacy top-level fields stay for compatibility (now documented as overlapping diagnostics) and timing.additiveParts provides disjoint parts that sum exactly to total — verified the arithmetic in the fixtures (10642 + 1993 + 14702 = 27337, which is the real measurement from #1046 turned into the test). 296 tests + provider 87/87 + typecheck green locally. The prepare help-text rewrite also quietly improved the CI guidance — good touch.