fix(notifications): truncate X post attachment titles in notification list

[AmarTrebinjac]

Summary

• Apply CSS line-clamp-3 truncation to notification attachment titles for SourcePostAdded, UserPostAdded, and SquadPostAdded notification types
• Thread notificationType prop from NotificationItem down to NotificationItemAttachment to enable conditional styling
• Uses the existing multi-truncate line-clamp-3 pattern already established in InAppNotificationItem and social card components

Key decisions

• Scoped by notification type, not post type: The notification attachment model doesn't carry PostType, so we scope by the three notification types that can produce X post attachments. For non-X posts under these types, article titles are naturally short and won't hit the 3-line clamp.
• CSS-only approach: Retroactively fixes all existing notifications. Full text preserved in DOM for accessibility. No backend/schema changes needed.
• line-clamp-3: Matches the existing InAppNotificationItem pattern (~3 visible lines).

Test plan

• All 14 existing NotificationItem.spec.tsx tests pass
• Manual QA: verify X post notification attachments truncate to ~3 lines with ellipsis
• Manual QA: verify other notification type attachments are unaffected

Closes ENG-1258

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Created by Huginn 🐦‍⬛

Preview domain

https://eng-1258-truncate-x-notification.preview.app.daily.dev

[vercel]

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Project	Deployment	Actions	Updated (UTC)
daily-webapp	Ready	Preview	Apr 15, 2026 0:57am

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
storybook	Ignored		Apr 15, 2026 0:57am

[AmarTrebinjac]

@claude fix build errors

[claude]

Claude finished @AmarTrebinjac's task in 15m 57s —— View job

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Fixed build errors

• Gather context and read changed files
• Identify build errors — typecheck_strict_changed CI step catches 8 strict TS errors in NotificationItem.tsx because the file was touched by this PR
• Fix strict TypeScript errors in NotificationItem.tsx
• Verify type check passes (Changed TypeScript files passed strict migration guard.)
• All 14 NotificationItem.spec.tsx tests still pass
• Commit and push fixes

What was fixed

The typecheck_strict_changed CI job runs strict TypeScript on every file changed by the PR. Since NotificationItem.tsx was touched, 8 pre-existing strict-mode violations were surfaced:

Line	Error	Fix
93	Icon() return type was ReactElement but returned null	Changed to ReactElement | null
110–112	label returned null but was typed as string	Return '' instead (required by MenuItemProps.label: string)
121–123	notificationMutingCopy[type] is ActionCopy | undefined (Partial record), copy accessed without guard	Added if (!copy) return ''; guard
148	NotificationItem return type was ReactElement but returned null when !isReady	Changed to ReactElement | null
168	description is string | undefined, but useObjectPurify requires Record<string, string | Node>	Used description ?? '' — this also resolved the downstream string | Node not assignable to string | TrustedHTML errors on lines 263 & 272
Branch