feat: compute and cache RoomInfo::active_service_members

[jmartinesp]

Changes

• Add a new RoomSummary::active_room_members field that will be used as a cache.
• Rename Room::active_service_members to Room::update_active_service_members, which will compute new values for the cache.
• Also reset this cached value when the member counts change in sync responses.
• Rename async fn Room::is_dm to Room::compute_is_dm and also trigger Room::update_active_service_members to re-calculate the cache.
• Add a new synchronous Room::is_dm function that will use the cached active_service_members value or calculate an approximate value as a fallback.
• Then expose this Room::compute_is_dm and Room::is_dm in RoomInfo, NotificationRoomInfo and SpaceRoom.

Motivation

For both the room list filtering and the SpaceRoom instances we can't rely on an accurate value computed in place, since those APIs are synchronous. The approximate value previously calculated could be wrong in several cases, so if we can compute a better one instead that should make the checks more accurate.

• I've documented the public API Changes in the appropriate CHANGELOG.md files.
• This PR was made with the help of AI.

Signed-off-by:

[codecov]

Codecov Report

❌ Patch coverage is 87.69231% with 24 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.91%. Comparing base (8b13e48) to head (20a48b4).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/matrix-sdk-base/src/room/mod.rs	62.06%	8 Missing and 3 partials ⚠️
crates/matrix-sdk-base/src/room/room_info.rs	96.62%	3 Missing ⚠️
crates/matrix-sdk/src/room/mod.rs	84.21%	0 Missing and 3 partials ⚠️
crates/matrix-sdk-ui/src/notification_client.rs	0.00%	0 Missing and 2 partials ⚠️
crates/matrix-sdk-ui/src/spaces/room.rs	33.33%	0 Missing and 2 partials ⚠️
crates/matrix-sdk/src/message_search.rs	0.00%	0 Missing and 2 partials ⚠️
...x-sdk-ui/src/room_list_service/filters/category.rs	98.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6537      +/-   ##
==========================================
- Coverage   89.91%   89.91%   -0.01%     
==========================================
  Files         381      381              
  Lines      105914   106006      +92     
  Branches   105914   106006      +92     
==========================================
+ Hits        95237    95315      +78     
- Misses       7028     7038      +10     
- Partials     3649     3653       +4     

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[codspeed-hq]

Merging this PR will not alter performance

✅ 50 untouched benchmarks

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_{Comparing feat/cache-active-service-member-count-in-room-info (20a48b4) with main (2ec031b)}