feat: add proxy lease runner diagnostics

[thymikee]

Summary

Adds diagnostics-only logical lease context to local/proxy iOS runner startup and busy-runner errors without weakening the on-disk runner file lease.

Updates CLI help and remote proxy docs to describe connect proxy, lazy lease allocation on open, five-minute inactivity expiry, and disconnect release. Runner language is scoped to local/proxy iOS while limrun/cloud remain provider interactor concerns.

Also refactors the Worker D diagnostic context so core/daemon code uses a shared runner lease context type instead of importing the iOS runner lease module directly.

Related PR Context

This PR is the Worker D slice only. It is intended to stack after:

• Plan 001: canonical provider-aware DeviceLease model.
• Plan 002 / feat: add proxy connect provider #889: connect proxy profile/materialization and lazy proxy lease allocation.
• Plan 003: daemon session admission, heartbeat, close release, and expiry cleanup.

The integrated reconciled stack is now in #890. Review #890 for the end-to-end behavior and use this PR as the isolated runner/docs slice if reviewing changes independently.

Validation

Ran pnpm format, pnpm exec vitest run src/platforms/ios/__tests__/runner-session.test.ts src/utils/__tests__/args.test.ts (186 tests passed), and pnpm typecheck.

[github-actions]

PR Preview Action v1.8.1
Preview removed because the pull request was closed.
2026-06-26 11:35 UTC

[github-actions]

Size Report

Metric	Base	Current	Diff
JS raw	1.3 MB	1.3 MB	+964 B
JS gzip	437.1 kB	437.2 kB	+109 B
npm tarball	575.0 kB	575.2 kB	+173 B
npm unpacked	1.9 MB	1.9 MB	+964 B

Startup median (7 runs, lower is better):

Scenario	Base	Current	Diff
CLI --version	29.9 ms	28.9 ms	-1.0 ms
CLI --help	50.4 ms	49.2 ms	-1.2 ms

Top changed chunks:

Chunk	Raw diff	Gzip diff
dist/src/9722.js	+1.7 kB	+503 B
dist/src/cli.js	-894 B	-391 B
dist/src/cli-help.js	+49 B	-43 B
dist/src/session.js	+81 B	+26 B

[thymikee]

Coordinator update: this PR is the isolated runner diagnostics/docs slice. The reconciled end-to-end leasing stack is now in #890, which folds this work together with the canonical lease model, connect-proxy provider, and daemon session admission/expiry cleanup. Review #890 for integrated behavior; keep this PR for focused runner/docs review if needed.

[thymikee]

Closing as superseded by #890, which integrates the lease contract, proxy connect, session admission/expiry, and diagnostics work. Please continue review there.