Low-severity fixes: scroll gate, media cache footprint, preview attribution, dead branch

[mubarakcoded]

Four self-contained low-severity fixes, each in its own commit. All app-side Swift; no engine/binding changes.

• Transcript non-interactive after a mid-fling chat switch. isActivelyScrolling gates .allowsHitTesting on the transcript but was never reset on a chat switch. The fresh inner ScrollView starts idle without emitting a phase transition, so a flag left true from the previous chat's fling left the new transcript's first tap silently ignored until the next scroll. Reset it in the existing onChange(of: chat.id) block alongside its siblings.
• Media cache footprint under-count on failed purge. purgeAll swallowed a removal failure and then zeroed trackedFootprint unconditionally. If entries survived on disk, that false zero was never reconciled (only a nil footprint re-seeds from an authoritative scan), so the eviction cap under-enforced indefinitely. Now the footprint is zeroed only when removal actually succeeds and nil'd on failure, matching purgeAccount.
• Media-only group previews were unattributed. The chat-list preview returned the "Attachment" fallback before the sender-prefix block, so a media-only message from a peer in a group showed a bare "Attachment" with no sender name while a text message from the same peer was attributed. Resolve the body first, then apply the incoming-group sender prefix uniformly to both.
• Dead branch in moveChatToArchived. The two arms gated on shouldEnrich ran byte-identical code. Collapsed to the single unconditional form; behavior-preserving.

Closes #452
Closes #453
Closes #471
Closes #472

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Summary by CodeRabbit

• Bug Fixes
  • Chat previews now consistently include the sender’s name, even for attachment-only and unsupported/empty messages.
  • Switching chats no longer leaves scrolling disabled for the newly opened conversation.
  • Moving chats to Archived now preserves enrichment-resolved metadata consistently.
  • Media cache purge now updates tracking correctly based on actual filesystem removal results.
• Tests
  • Reworked media-disk-cache deletion regression coverage, including cases where sealed metadata cannot be opened.
  • Updated media fallback chat-list preview assertions to include sender attribution.

[stage-review]

Ready to review this PR? Stage has broken it down into 4 individual chapters for you:

	Title
1	Reset scroll gate on chat switch
2	Fix media cache footprint tracking on failure
3	Attribute media-only group previews to senders
4	Collapse redundant branches in chat archiving

_{Chapters generated by Stage for commit 2ae2055 on Jul 13, 2026 10:54am UTC.}

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Configuration used: Organization UI

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Run ID: 5635d318-b65c-4281-b9eb-f4a11033cb9e

📥 Commits

Reviewing files that changed from the base of the PR and between a1d06e6 and 2ae2055.

📒 Files selected for processing (2)

• whitenoise-mac/Core/MessageMediaDiskCache.swift
• whitenoise-macTests/whitenoise_macTests.swift

🚧 Files skipped from review as they are similar to previous changes (1)

• whitenoise-mac/Core/MessageMediaDiskCache.swift

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Walkthrough

The changes fix four independent behaviors: sender attribution for attachment previews, cache footprint handling after failed purges, metadata preservation during archive moves, and scroll-state reset when switching conversations.

Changes

Message preview attribution

Layer / File(s)	Summary
Build and validate prefixed preview bodies whitenoise-mac/Core/MarmotMapping.swift, whitenoise-macTests/whitenoise_macTests.swift	Preview fallbacks are constructed before sender-name prefixes are applied, with direct and group chat tests expecting attributed attachment text.

Cache purge accounting

Layer / File(s)	Summary
Handle purge removal outcomes whitenoise-mac/Core/MessageMediaDiskCache.swift, whitenoise-macTests/whitenoise_macTests.swift	Cache removal checks existence and success, resetting trackedFootprint on success or setting it to nil after failure; cache tests cover corrupt metadata deletion behavior.

Archived chat metadata

Layer / File(s)	Summary
Preserve resolved archive metadata whitenoise-mac/Core/WorkspaceState+ChatList.swift	Archived chat moves preserve enrichment-resolved metadata whenever an active chat exists, regardless of shouldEnrich.

Conversation scroll state

Layer / File(s)	Summary
Reset scroll interaction state whitenoise-mac/Views/MessengerShellView.swift	Changing chats now resets isActivelyScrolling for the newly mounted conversation.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related issues

• CI: restore the macOS PR test plan after media-cache changes #457: Updates the same media-cache deletion regression test for corrupt metadata and cache-entry removal behavior.

Possibly related PRs

• marmot-protocol/whitenoise-mac#204: Updates related attachment and unsupported-message preview handling.
• marmot-protocol/whitenoise-mac#277: Updates per-chat state resets in the conversation change handler.
• marmot-protocol/whitenoise-mac#380: Changes MessageMediaDiskCache purge and eviction tracking behavior.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is concise and matches the four fixes in the changeset.
Linked Issues check	✅ Passed	The PR covers the linked fixes for #452, #453, #471, and #472.
Out of Scope Changes check	✅ Passed	The changes stay within the four stated bugfix/refactor objectives; tests and comment updates are supporting.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@whitenoise-mac/Core/MessageMediaDiskCache.swift`:
- Around line 318-334: Update the purge closure around beginPurge and
trackedFootprint so removalSucceeded starts false, becomes true only when
directoryResolver resolves a root and that root is either absent or successfully
removed, and remains false when resolution fails. Preserve the existing
encryption-key deletion and nil-versus-zero trackedFootprint behavior.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: faaccbf2-dd90-4ca7-aeb2-f469169c36b6

📥 Commits

Reviewing files that changed from the base of the PR and between 0454dbf and 144a328.

📒 Files selected for processing (4)

• whitenoise-mac/Core/MarmotMapping.swift
• whitenoise-mac/Core/MessageMediaDiskCache.swift
• whitenoise-mac/Core/WorkspaceState+ChatList.swift
• whitenoise-mac/Views/MessengerShellView.swift