fix(events): bound provider prefix recent query

apps/api/tests/test_awooop_conversation_event_hot_path_indexes.py

@@ -1,5 +1,7 @@
 from pathlib import Path
 
+from src.services.platform_operator_service import _provider_event_id_prefix_bounds
+
 ROOT = Path(__file__).resolve().parents[1]
 MIGRATION = "awooop_conversation_event_hot_path_indexes_2026-07-01.sql"
 ROLLBACK = "awooop_conversation_event_hot_path_indexes_2026-07-01_down.sql"
@@ -57,9 +59,9 @@ def test_provider_recent_indexes_match_live_hot_queries() -> None:
 
     assert "COALESCE(NULLIF(source_envelope->>'provider', '')" in coverage_source
     assert "ORDER BY received_at DESC" in coverage_source
-    assert "LOWER(COALESCE(NULLIF(source_envelope->>'provider', '')" in operator_source
-    assert "recent_provider_prefix" in operator_source
-    assert "NULLIF(split_part(provider_event_id, ':', 1), '')" in operator_source
+    assert "_provider_event_id_prefix_bounds" in operator_source
+    assert "provider_event_id >= prefix_lower" in operator_source
+    assert "provider_event_id < prefix_upper" in operator_source
 
     assert "idx_awooop_conv_event_project_provider_recent" in sql
     assert "idx_awooop_conv_event_project_provider_lower_recent" in sql
@@ -69,6 +71,18 @@ def test_provider_recent_indexes_match_live_hot_queries() -> None:
     assert "event_id DESC" in sql
 
 
+def test_recent_provider_prefix_uses_btree_range_bounds() -> None:
+    assert _provider_event_id_prefix_bounds("alertmanager") == (
+        "alertmanager:",
+        "alertmanager;",
+    )
+    assert _provider_event_id_prefix_bounds("alertmanager:received") == (
+        "alertmanager:received",
+        "alertmanager:receivee",
+    )
+    assert _provider_event_id_prefix_bounds(" SignOz ") == ("signoz:", "signoz;")
+
+
 def test_truth_chain_source_lookup_indexes_match_or_terms() -> None:
     sql = _migration_sql()
     truth_chain_source = _read("src/services/awooop_truth_chain_service.py")