Make timeline sender avatars and display names update reactively

[jennaharris7]

Content

Let live RoomMember updates override the event-level sender snapshot in TimelineItemEventFactory, so timeline rows already in the diff cache reflect avatar / display name changes that arrived via sync. Banned members keep the existing hide-identity behavior.

Motivation and context

Closes #5176. Customers report that when another user changes their avatar or display name, the update doesn't appear until the app is restarted or the cache is cleared.

The issue was tagged X-Needs-Rust, but no matrix-rust-sdk change turned out to be necessary: the SDK already emits profile changes as ProfileChangeContent timeline events. The only SDK-layer tweak is in MatrixTimelineDiffProcessor, which now treats ProfileChangeContent (alongside the already-handled RoomMembershipContent) as a trigger for membershipChangeEventReceived so subscribers refresh the cached members list.

Open question

Do we want this behind a feature flag for users who may want to keep the behavior of seeing historical snapshots of timeline events?

Screenshots / GIFs

Tests

• New unit tests for ProfileDetails.withLiveMemberOverride: live member wins, null falls back, banned falls back, ambiguous name propagates, Unavailable snapshot still uses live data.
• Manual: change a peer's avatar from another client, confirm the timeline reflects it without restarting EXA.

Tested devices

• Physical
• Emulator
• OS version(s): Samsung Galaxy S24, Android 16

Checklist

• This PR was made with the help of AI:
  • Yes. In this case, please request a review by Copilot.
• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account.
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly defines what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

[CLAassistant]

All committers have signed the CLA.

[github-actions]

📱 Scan the QR code below to install the build (arm64 only) for this PR.

If you can't scan the QR code you can install the build via this link: https://i.diawi.com/aTdu8x

[codecov]

Codecov Report

❌ Patch coverage is 94.11765% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.16%. Comparing base (e8f1bf0) to head (560101d).
⚠️ Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
...es/impl/timeline/factories/TimelineItemsFactory.kt	60.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6775      +/-   ##
===========================================
+ Coverage    81.14%   81.16%   +0.02%     
===========================================
  Files         2647     2647              
  Lines        74099    74119      +20     
  Branches      9600     9601       +1     
===========================================
+ Hits         60126    60162      +36     
+ Misses       10438    10423      -15     
+ Partials      3535     3534       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[jmartinesp]

Sorry for the long review time, the code looks good to me overall. About this question:

Do we want this behind a feature flag for users who may want to keep the behavior of seeing historical snapshots of timeline events?

I'd say we do, I think when we implemented this in the classic apps we did so behind a developer option/advanced settings toggle. @mxandreas WDYT?

[jmartinesp]

Actually, it seems like this should be possible with a pure SDK implementation: matrix-org/matrix-rust-sdk#6575

I'm looking at ways to implement this, it seems like following the example from AmbiguityMap would do the trick.

[jmartinesp]

Since matrix-org/matrix-rust-sdk#6576 was merged, this should now be fixed in the SDK and we can probably close this PR. Thanks again for the client-side fix, but it's better to have it centralised in the SDK.