fix: defer composer height measurements

[agent-p1p]

Fixes #469

Summary

• defer the initial composer height measurement until after makeNSView returns
• remove the duplicate synchronous measurement from updateNSView and retain its deferred measurement
• keep direct measurement in textDidChange, which runs from the AppKit delegate event rather than SwiftUI's representable update transaction

Verification

• git diff --check — passed
• static lifecycle inspection — both makeNSView and updateNSView contain exactly one deferred measurement and no synchronous binding write
• scripts/ci/macos-sanity-checks.sh — unavailable on this Linux host (xcodebuild: command not found)
• xcrun swift-format lint --configuration .swift-format --recursive --parallel --strict whitenoise-mac whitenoise-macTests whitenoise-macUITests — unavailable on this Linux host (xcrun: command not found)
• Xcode unit test command — unavailable on this Linux host (xcodebuild: command not found)

No regression test was added: this bug is specifically SwiftUI/AppKit lifecycle scheduling, and a meaningful behavior test requires macOS execution. A source-scrape test or test-only visibility hook would be more brittle and complex than the two-call fix. CI will run the native checks.

Sensitive paths

None.

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Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: e011459a-56c3-425d-a588-5b190b56a9a4

📥 Commits

Reviewing files that changed from the base of the PR and between 490ca5b and 8edcd5e.

📒 Files selected for processing (1)

• whitenoise-mac/Views/ComposerViews.swift

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch pip/whitenoise-mac-469

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[stage-review]

Ready to review this PR? Stage has broken it down into 1 individual chapter for you:

	Title
1	Defer composer height measurements

_{Chapters generated by Stage for commit 8edcd5e on Jul 13, 2026 12:41pm UTC.}

[agent-p1p]

Adversarial review

Verdict: implementation is correct; no code changes requested. Merge remains blocked by red CI.

Code review

• makeNSView now schedules height measurement after the representable lifecycle transaction instead of writing the parent @State synchronously.
• updateNSView retains only its existing deferred measurement. There is no lifecycle-path synchronous write left.
• The immediate call in textDidChange is appropriate: it runs from the AppKit edit delegate, not from SwiftUI's representable update transaction, and preserves responsive growth while typing.
• Scope is minimal: one file, 3 additions / 2 deletions, no sensitive paths, no unrelated abstraction or state.

Blocking — workflow / CI

The PR's PR Checks job failed. The full 418-test plan recorded three expectations in messageMediaDiskCacheReadDeletionMaintainsTrackedFootprint() and skipped the release smoke step:
https://github.com/marmot-protocol/whitenoise-mac/actions/runs/29178456073

This is demonstrably pre-existing and unrelated to this SwiftUI-only diff: the same test and same three assertions fail on base commit 0454dbf's master run:
https://github.com/marmot-protocol/whitenoise-mac/actions/runs/29100021269

Existing issue #457 tracks the broken baseline test. No scope expansion is requested here, but Pip policy forbids merging any PR that has had red CI, so this remains a workflow blocker for #474.

Verification

• git diff --check origin/master...0ed5357 — passed
• CI Swift format lint — passed
• CI macOS project sanity checks — passed
• CI Static Analysis — passed
• CI unit tests — failed only in the unrelated baseline media-cache test above
• CodeRabbit review was rate-limited; it posted no findings

Counts: 1 blocking workflow finding, 0 code blockers, 0 suggestions, 0 nitpicks.