perf: speed up iOS simulator screenshots

[thymikee]

Summary

Skip the redundant ensureBootedSimulator probe for session-backed iOS simulator screenshots. The simulator screenshot path already uses xcrun simctl io <udid> screenshot <path> and keeps physical devices/macOS on their existing paths; this change avoids an extra simctl list devices -j call once the daemon has an active simulator session.

Closes #916

Touched files: 8. Scope stayed within screenshot command/runtime handoff, iOS simulator screenshot path selection, and focused tests.

Validation

Static and focused checks passed:

• node ./node_modules/oxfmt/bin/oxfmt --write ...
• ./node_modules/.bin/vitest run --project unit src/platforms/ios/__tests__/index.test.ts src/daemon/__tests__/request-router-screenshot.test.ts - 101 tests passed
• ./node_modules/.bin/tsc -p tsconfig.json
• ./node_modules/.bin/oxlint . --deny-warnings
• ./node_modules/.bin/rslib build
• node --test test/integration/smoke-*.test.ts - 8 passed, 1 skipped
• ./node_modules/.bin/vitest run --project unit --testTimeout=15000 - 285/286 files passed; one unrelated daemon-client cleanup assertion failed in the aggregate run, then ./node_modules/.bin/vitest run --project unit src/utils/__tests__/daemon-client.test.ts --testTimeout=15000 passed 28/28 on rerun. The unrelated Android file that failed with default timeout also passed on rerun with --testTimeout=15000.

Simulator evidence on iPhone 17 simulator D74E0B66-57EB-4EC1-92DC-DA0A30581FE7, iOS 26.2, Settings app session:

• Bare candidate xcrun simctl io <udid> screenshot <path>: 1418, 1102, 1594, 2633, 2582 ms; median 1594 ms.
• Public agent-device screenshot before this change, after open settings: 5164, 4939, 5439, 5152, 5194 ms; median 5164 ms.
• Public agent-device screenshot after this change, after rebuild/daemon cleanup/open: 5636, 4739, 4699, 4838, 4905 ms; median 4838 ms.

The remaining gap is mostly simulator status-bar normalization/restoration, measured separately as roughly 700-970 ms per status_bar command. This PR keeps that behavior to preserve deterministic screenshots and host simulator state restoration.

[github-actions]

Size Report

Metric	Base	Current	Diff
JS raw	1.4 MB	1.4 MB	+289 B
JS gzip	445.6 kB	445.7 kB	+121 B
npm tarball	586.2 kB	586.3 kB	+111 B
npm unpacked	2.0 MB	2.0 MB	+289 B

Startup median (7 runs, lower is better):

Scenario	Base	Current	Diff
CLI --version	26.3 ms	26.2 ms	-0.1 ms
CLI --help	47.5 ms	47.5 ms	+0.0 ms

Top changed chunks:

Chunk	Raw diff	Gzip diff
dist/src/9722.js	+167 B	+60 B
dist/src/apps.js	+68 B	+37 B