fix(bqaa): put C7 pair keys under attributes.adk (not top-level)

Caught in review of #6: the C7 pair keys
(pause_kind, function_call_id) were being passed via
EventData.extra_attributes, which _enrich_attributes() copies at the
top of attrs *before* attrs["adk"] = _build_adk_envelope(...). That
landed them at attributes.pause_kind / attributes.function_call_id,
not attributes.adk.pause_kind / attributes.adk.function_call_id.

The customer SQL pinned in google#293 v5 acceptance #3 is:

  JSON_VALUE(attributes, '$.adk.function_call_id') = JSON_VALUE(...)

so the pair join would have returned null on every row. This commit
makes the contract match the SQL.

Changes:
* EventData gains adk_extras: dict[str, Any], a sibling of
  extra_attributes that lives INSIDE attributes.adk.
* _enrich_attributes merges adk_extras into the envelope after
  _build_adk_envelope (envelope wins on conflict — producer-derived
  identity fields like source_event_id are the source of truth).
* The two emit sites (TOOL_PAUSED in on_event_callback,
  TOOL_COMPLETED in on_user_message_callback) pass the pair keys via
  adk_extras= instead of extra_attributes=.
* The three C7 tests are updated to assert
  json.loads(row["attributes"])["adk"]["pause_kind"] etc., locking
  in the right shape this time.

Full plugin suite: 252 passed.

Author: caohy1988

src/google/adk/plugins/bigquery_agent_analytics_plugin.py

@@ -2020,6 +2020,12 @@ class EventData:
   # an Event — the envelope helper writes those attributes as null
   # rather than synthesizing fake identity (per #293 v5 A3 contract).
   source_event: Optional["Event"] = None
+  # Producer-supplied extras that belong INSIDE ``attributes.adk`` (not
+  # at the top level of ``attributes``). C7's pair keys
+  # (``pause_kind`` / ``function_call_id``) ride here so consumer SQL
+  # like ``JSON_VALUE(attributes, '$.adk.function_call_id')`` lands at
+  # the right JSON path per #293 v5.
+  adk_extras: dict[str, Any] = field(default_factory=dict)
 
 
 class BigQueryAgentAnalyticsPlugin(BasePlugin):
@@ -2923,9 +2929,17 @@ def _enrich_attributes(
         A new dict ready for JSON serialization into the attributes column.
     """
     attrs: dict[str, Any] = dict(event_data.extra_attributes)
-    attrs["adk"] = self._build_adk_envelope(
+    adk_envelope = self._build_adk_envelope(
         callback_context, event_data.source_event
     )
+    # Merge producer-supplied adk_extras (#293 v5 C7 pair keys etc.)
+    # INTO the adk envelope so consumer SQL on
+    # ``$.adk.pause_kind`` / ``$.adk.function_call_id`` resolves.
+    # adk_envelope wins on key conflict — producer-derived envelope
+    # is the source of truth for identity fields like source_event_id.
+    for k, v in event_data.adk_extras.items():
+      adk_envelope.setdefault(k, v)
+    attrs["adk"] = adk_envelope
 
     attrs["root_agent_name"] = TraceManager.get_root_agent_name()
     if event_data.model:
@@ -3136,7 +3150,7 @@ async def on_user_message_callback(
               raw_content=content_dict,
               is_truncated=is_truncated,
               event_data=EventData(
-                  extra_attributes={
+                  adk_extras={
                       "pause_kind": "tool",
                       "function_call_id": part.function_response.id,
                   },
@@ -3304,7 +3318,7 @@ async def on_event_callback(
                 is_truncated=is_truncated,
                 event_data=EventData(
                     source_event=event,
-                    extra_attributes={
+                    adk_extras={
                         "pause_kind": pause_kind,
                         "function_call_id": part.function_call.id,
                     },

tests/unittests/plugins/test_bigquery_agent_analytics_plugin.py

@@ -8007,7 +8007,6 @@ async def test_skips_executable_code_only_events(
     assert mock_write_client.append_rows.call_count == 0
 
 
-
 # -----------------------------------------------------------------------------
 # ADK 2.0 minimum producer cut (#293 v5)
 #
@@ -8346,10 +8345,11 @@ async def test_tool_paused_non_hitl_pause_kind_tool(
     rows = await _get_captured_rows_async(mock_write_client, dummy_arrow_schema)
     pauses = [r for r in rows if r["event_type"] == "TOOL_PAUSED"]
     assert len(pauses) == 1
+    # C7 pair keys live UNDER ``attributes.adk`` so the consumer SQL on
+    # ``JSON_VALUE(attributes, '$.adk.function_call_id')`` resolves.
     adk = json.loads(pauses[0]["attributes"])["adk"]
-    extras = json.loads(pauses[0]["attributes"])
-    assert extras["pause_kind"] == "tool"
-    assert extras["function_call_id"] == "call-1"
+    assert adk["pause_kind"] == "tool"
+    assert adk["function_call_id"] == "call-1"
 
   @pytest.mark.asyncio
   async def test_tool_paused_hitl_pause_kind(
@@ -8379,9 +8379,9 @@ async def test_tool_paused_hitl_pause_kind(
     rows = await _get_captured_rows_async(mock_write_client, dummy_arrow_schema)
     pauses = [r for r in rows if r["event_type"] == "TOOL_PAUSED"]
     assert len(pauses) == 1
-    extras = json.loads(pauses[0]["attributes"])
-    assert extras["pause_kind"] == "hitl_confirmation"
-    assert extras["function_call_id"] == "call-hitl-1"
+    adk = json.loads(pauses[0]["attributes"])["adk"]
+    assert adk["pause_kind"] == "hitl_confirmation"
+    assert adk["function_call_id"] == "call-hitl-1"
 
   @pytest.mark.asyncio
   async def test_user_message_function_response_emits_tool_completed(
@@ -8407,9 +8407,9 @@ async def test_user_message_function_response_emits_tool_completed(
     rows = await _get_captured_rows_async(mock_write_client, dummy_arrow_schema)
     completed = [r for r in rows if r["event_type"] == "TOOL_COMPLETED"]
     assert len(completed) == 1
-    extras = json.loads(completed[0]["attributes"])
-    assert extras["pause_kind"] == "tool"
-    assert extras["function_call_id"] == "call-1"
+    adk = json.loads(completed[0]["attributes"])["adk"]
+    assert adk["pause_kind"] == "tool"
+    assert adk["function_call_id"] == "call-1"
 
   @pytest.mark.asyncio
   async def test_hitl_user_message_does_not_emit_tool_completed(