feat(occurrences on eap): Implement EAP read for group hourly count (is_escalating algorithm)

[shashjar]

Using an EndpointTraceItemTable RPC query to fetch the count of occurrences for a specific group in the current hour.

Tested locally to ensure that the count aggregation is coming back correctly from EAP:

sentry.utils.snuba_rpc: Running a EndpointTraceItemTable RPC query (rpc_query={'meta': {'organizationId': '1', 'cogsCategory': 'issues', 'referrer': 'issues.escalating', 'projectIds': ['2'], 'startTimestamp': '2025-12-12T00:00:00Z', 'endTimestamp': '2025-12-12T00:01:01.209821Z', 'traceItemType': 'TRACE_ITEM_TYPE_OCCURRENCE'}, 'columns': [{'aggregation': {'aggregate': 'FUNCTION_COUNT', 'key': {'type': 'TYPE_INT', 'name': 'group_id'}}, 'label': 'count'}], 'filter': {'comparisonFilter': {'key': {'type': 'TYPE_INT', 'name': 'group_id'}, 'op': 'OP_EQUALS', 'value': {'valInt': '3'}}}, 'limit': 1} referrer='issues.escalating' organization_id=1 trace_item_type=7)

sentry.utils.snuba_rpc: Table RPC query response (rpc_rows=1 page_token=offset: 1
 meta=request_id: "ce96e6d07c544b2eaec75707ff21a5a4"
query_info {
  stats {
    progress_bytes: 1674
  }
  metadata {
  }
}
downsampled_storage_meta {
}
)

sentry.issues.escalating.escalating: 
get_group_hourly_count_eap: raw response (group_id=3 raw_response='column_values {\n  attribute_name: "count"\n  results {\n    val_double: 6\n  }\n}\npage_token {\n  offset: 1\n}\nmeta {\n  request_id: "ce96e6d07c544b2eaec75707ff21a5a4"\n  query_info {\n    stats {\n      progress_bytes: 1674\n    }\n    metadata {\n    }\n  }\n  downsampled_storage_meta {\n  }\n}\n')

sentry.issues.escalating.escalating: 
is_escalating: old_count=6, new_count=6

To roll this out, we can:

1. Merge in this PR (no change in behavior in any region)
2. Flip the occurrences.eap-reads.enabled option on for the S4S region only
3. At this point, we'll be calculating both values in S4S but sticking with the Snuba value as the source of truth
4. We should see the issues.escalating.eap_mismatch metric start getting recorded and then converge to 0 over time (as EAP gets up-to-speed on all the groups within retention)
5. At that point (01/21/2026, 90 days after 10/23/2025), we should be able to remove the legacy read path and use EAP only

[shashjar]

Should we wait until we've worked on a couple more read paths to consolidate this logic? I feel like it's hard at this point to say exactly what kind of abstraction we want.

[codecov]

Codecov Report

❌ Patch coverage is 97.72727% with 1 line in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/sentry/issues/escalating/escalating.py	97.67%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #104830   +/-   ##
========================================
  Coverage   80.49%    80.49%           
========================================
  Files        9370      9370           
  Lines      402213    402255   +42     
  Branches    25837     25837           
========================================
+ Hits       323744    323788   +44     
+ Misses      78021     78019    -2     
  Partials      448       448