fix(sync): avoid invalid MLS reset state

[MohamadJaara]

Intent

Avoid persisting an incorrect MLS reset state when the new group cannot be inspected.

Root cause

The reset handler converted a failed established-group check to false. That made an unavailable or failed check indistinguishable from a confirmed non-established group, so the conversation could be written as PENDING_AFTER_RESET even though the real group state was unknown.

The established-group path also read the epoch directly instead of using the repository's failure-aware wrapper.

Reproduction

1. Deliver an MLSReset event.
2. Make the established-group check fail.
3. Observe the failure become false.
4. Observe the handler attempt to persist the new group as pending.

Fix

The handler now stops the reset state transition when either the established-group check or the new-group epoch lookup fails. Epoch lookup uses the repository wrapper, and handling failures are logged inside the handler.

Leaving the old group remains best-effort because a replay may find it already absent. The receiver's existing acknowledgement behavior is unchanged; these failures are not newly propagated to its caller.

Regression coverage verifies that established-group and epoch lookup failures do not update the conversation state, while the established and pending success paths still do.

[github-actions]

Test Results

0 tests   - 5 871   0 ✅  - 5 730   0s ⏱️ - 4m 25s
0 suites  -   889   0 💤  -   141 
0 files    -   889   0 ❌ ±    0 

Results for commit dd1a5be. ± Comparison against base commit d57f18f.

♻️ This comment has been updated with latest results.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.31%. Comparing base (d57f18f) to head (a22b279).

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #4301   +/-   ##
==========================================
  Coverage      61.30%   61.31%           
  Complexity      4022     4022           
==========================================
  Files           2163     2163           
  Lines          69467    69463    -4     
  Branches        6901     6900    -1     
==========================================
- Hits           42590    42588    -2     
+ Misses         24114    24112    -2     
  Partials        2763     2763           

Files with missing lines	Coverage Δ
...m/logic/sync/receiver/ConversationEventReceiver.kt	86.44% <100.00%> (+4.47%)	⬆️
...r/conversation/MLSResetConversationEventHandler.kt	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

---

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[github-actions]

Bencher Report

Branch	${GITHUB_HEAD_REF}
Testbed	ubuntu-latest

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Benchmark	Latency	microseconds (µs)
com.wire.kalium.benchmarks.logic.CoreLogicBenchmark.createObjectInFiles	📈 view plot ⚠️ NO THRESHOLD	913.01 µs
com.wire.kalium.benchmarks.logic.CoreLogicBenchmark.createObjectInMemory	📈 view plot ⚠️ NO THRESHOLD	569,702.81 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.inboxPagingDeepPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	135,170.36 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.inboxPagingFirstPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	129,861.15 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.localMarkAsReadBenchmark	📈 view plot ⚠️ NO THRESHOLD	3,579.36 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.messagePagingDeepPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	38,204.58 µs
com.wire.kalium.benchmarks.persistence.MessageReadBenchmark.messagePagingFirstPageBenchmark	📈 view plot ⚠️ NO THRESHOLD	22,459.99 µs
com.wire.kalium.benchmarks.persistence.MessagesNoPragmaTuneBenchmark.messageInsertionBenchmark	📈 view plot ⚠️ NO THRESHOLD	1,385,926.75 µs
com.wire.kalium.benchmarks.persistence.MessagesNoPragmaTuneBenchmark.queryMessagesBenchmark	📈 view plot ⚠️ NO THRESHOLD	21,375.45 µs

🐰 View full continuous benchmarking report in Bencher

[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