fix(mobile): separate unfolded thread list from header

[PixPMusic]

What Changed

Built-in Android themes use the header color behind the thread list when a foldable is unfolded. Map the Android drawer surface to the screen color so the list keeps the same surface as the folded layout.

Why

The shared drawer token also paints unselected rows, swipe backgrounds, and provider icon cutouts. Updating that token fixes them together while preserving the header color, selected rows, Material You, and iOS.

UI Changes

Fresh native screenshots with showcase data on an Android 17 Pixel 9 Pro Fold emulator. Each pair uses the same theme, route, dimensions, and orientation.

State	Before	After
Iris dark, unfolded
Iris light, unfolded

Selected conversations and folded / Material You checks

State	Before	After
Iris dark, unfolded conversation
Iris dark, folded
Iris light, unfolded conversation
Iris light, folded
Material You dark, unfolded
Material You dark, unfolded conversation
Material You dark, folded

The synthetic failed-provider row appears in both captures after fixture server startup; it is unrelated to the color change. Relative time labels advance between captures.

Verification

• 62 focused tests passed across mobile theme variables, palette contrast, Material You, and thread-list row appearance.
• Mobile typecheck, scoped lint/format checks, and git diff --check passed.
• Fresh Android native debug build passed; verified Iris light/dark and Material You dark on cover and inner displays, with and without a selected conversation.
• iOS theme mapping is covered by existing tests; no iOS simulator pass.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes

Model: GPT-6 Astra | Harness: Codex in T3 Code

Summary by CodeRabbit

• Bug Fixes
  • Updated Android’s drawer background to match the screen surface for a more consistent appearance.
  • Improved drawer text contrast in Android light and dark themes to meet accessibility standards.
  • Corrected iPad dark mode so the drawer uses a true black background.
  • Refined platform-specific theme behavior to ensure sidebar and thread canvas colors display appropriately across iOS and Android.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — The change updates the Android drawer surface used by the thread list and related row backgrounds across built-in themes, producing an observable default UI change while leaving iOS and non-Android paths intact. Focused tests cover the theme mappings, contrast, and platform-specific behavior.

No code changes detected at 1f9bb76. Prior analysis still applies.

^{You can add or adjust custom eligibility rules. Learn more.}

[PixPMusic]

Not sure how this regressed. I swore this is how I had things in the last Material You PR...

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between aff9318 and 7506360bf573d5ba8ef9861ab65ea11a9df7d358.

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📒 Files selected for processing (3)

• apps/mobile/src/lib/mobileTheme.test.ts
• apps/mobile/src/lib/mobileThemeVariables.test.ts
• apps/mobile/src/lib/mobileThemeVariables.ts

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📝 Walkthrough

Walkthrough

The Android mobile theme now sets the drawer color to the screen color. Tests verify drawer text contrast and update platform-specific luminance expectations.

Changes

Android drawer palette

Layer / File(s)	Summary
Android drawer runtime color apps/mobile/src/lib/mobileThemeVariables.ts, apps/mobile/src/lib/mobileThemeVariables.test.ts	Android now uses --color-screen for --color-drawer. Tests verify this behavior.
Theme contrast and platform assertions apps/mobile/src/lib/mobileTheme.test.ts, apps/mobile/src/lib/mobileThemeVariables.test.ts	Android drawer foreground colors must meet a 4.5 contrast ratio. The sidebar luminance check is limited to iOS, and dark iOS uses #000000 for the drawer.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: juliusmarminge

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Merge Risk: ⚪ Minimal · up to 75063

Android unfolded layouts now use the screen color behind the thread list while preserving iOS behavior, with matching contrast and platform assertions. No merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the mobile layout fix: separating the unfolded thread list surface from the header. It is concise and related to the primary change.
Description check	✅ Passed	The description includes What Changed, Why, UI Changes with before-and-after screenshots, verification details, and a completed checklist. It explains the Android-specific behavior and test coverage c…
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 3 files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create a new PR

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[PixPMusic]

@juliusmarminge @maria-rcks This is rebased onto current main and ready for maintainer review. Mobile typecheck and scoped lint/format checks pass; existing before/after evidence is in the description.