perf(xmpp): fix slow MAM/MUC-MAM and move OMEMO decryption off the main

thread

- Replace O(n^2) origin-id/stanza-id lookups in AppModel with hash
  indexes
  and stop rebuilding the whole index on every unseen stanza-id, so
  archive
  application no longer grows quadratically with history size.
- Run OMEMO decryption on a serial background queue instead of the main
  actor, and decrypt archived stanzas in small batches with a shorter
  yield,
  keeping the UI responsive during large archive catch-ups.
- Show the "Синхронизация истории…" banner only for the one-page
  bootstrap
  window; incremental backlog catch-up continues silently in the
  background.
- Fix MUC-MAM: publish decoded group mutations at the end of room
  catch-up;
  they were previously accumulated and then silently dropped.
- Retry a failed catch-up pass automatically (bounded) and lengthen the
  query/apply timeouts so a single slow page no longer leaves history
  unloaded until the next app activation.

Tests/ArchiveSyncRecoveryPolicyTests.swift

@@ -10,7 +10,7 @@ final class ArchiveSyncRecoveryPolicyTests: XCTestCase {
         XCTAssertGreaterThan(ArchiveSyncRecoveryPolicy.queryTimeoutNanoseconds, 0)
         XCTAssertLessThanOrEqual(
             ArchiveSyncRecoveryPolicy.queryTimeoutNanoseconds,
-            15_000_000_000
+            20_000_000_000
         )
     }
 
@@ -26,6 +26,15 @@ final class ArchiveSyncRecoveryPolicyTests: XCTestCase {
         XCTAssertEqual(ArchiveSyncRecoveryPolicy.pageRetryLimit, 1)
     }
 
+    func testCatchUpRetryDelayAndCapAreBounded() {
+        XCTAssertGreaterThan(
+            ArchiveSyncRecoveryPolicy.retryAfterFailureDelayNanoseconds,
+            0
+        )
+        XCTAssertGreaterThan(ArchiveSyncRecoveryPolicy.maximumAutomaticRetries, 0)
+        XCTAssertLessThanOrEqual(ArchiveSyncRecoveryPolicy.maximumAutomaticRetries, 5)
+    }
+
     func testCaptureResumeDelayLetsCameraReleaseResources() {
         XCTAssertGreaterThan(
             ArchiveSyncRecoveryPolicy.resumeAfterCaptureDelayNanoseconds,