ci: empty-commit retrigger (all-required emitter stuck on cancelled canvas-deploy-reminder)

PR#1240 added workspace/a2a_tools_identity.py but did not update
scripts/build_runtime_package.py:TOP_LEVEL_MODULES, so the drift gate
fails on every publish-runtime tag push:

  error: TOP_LEVEL_MODULES drifted from workspace/*.py contents:
    in workspace/ but NOT in TOP_LEVEL_MODULES (will ship un-rewritten):
      ['a2a_tools_identity']

This blocked the post-PR#1240 cascade: PyPI publish never happened
because the package wouldn't build. Verified by observing runs 59570,
59587, and 59589 (publish-runtime.yml) all failing at the same step
with this exact error.

T4 close-out — Hongming-authorized direct merge.

scripts/build_runtime_package.py

@@ -58,6 +58,7 @@ TOP_LEVEL_MODULES = {
     "a2a_response",
     "a2a_tools",
     "a2a_tools_delegation",
+    "a2a_tools_identity",
     "a2a_tools_inbox",
     "a2a_tools_memory",
     "a2a_tools_messaging",