[ludoch]

RuntimeJarDependencyClosureTest (CI guard)

Adds runtime/test/src/test/java/com/google/apphosting/runtime/RuntimeJarDependencyClosureTest.java, parameterized over runtime-impl-jetty12.jar and runtime-impl-jetty121.jar:

• Runs jdeps -verbose:class (through ToolProvider) on the jar from the runtime deployment, with runtime-main.jar and the runtime-shared-*.jar on the class path.
• Walks every class reachable from com.google.appengine.* / com.google.apphosting.* through the bundled libraries.
• Fails on any missing class outside a short KNOWN_MISSING_PACKAGES list. The listed exceptions are pre-existing, on unused paths, each with a reason: antlr for the borgcron Groc parser, google-api-client for the Cloud Datastore v1 client, io.grpc.alts (DirectPath), Jetty ALPN, and JNDI transactions.
• The failure message lists each missing class with the reference chain, e.g. com.google.auth.Credentials <- com.google.appengine.api.taskqueue.CloudTasksClientWrapper.
• Skipped (assumption) if jdeps isn't available (JRE only). It takes about 4 s per jar.

Verified:
Both runtime-impl-jetty12.jar and runtime-impl-jetty121.jar pass:

[INFO] Running com.google.apphosting.runtime.RuntimeJarDependencyClosureTest
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 5.511 s

[ludoch]

Verified that the new skills in .agent/skills/ are picked up and work as expected in Antigravity (agy CLI) as well:

• Skills (runtime-jar-deps, pom-dependency-change, internal-runtime-usage, runtime-e2e-tests) are discovered and loaded into the agent context automatically.
• Executed the verification workflow specified in runtime-jar-deps by running RuntimeJarDependencyClosureTest (passed cleanly: 2 tests run, 0 failures).
• Verified the companion script .agent/skills/pom-dependency-change/scripts/jar_size_diff.sh is executable and functional.

[maigovannon]

@gajjarc do we still need this?

[ludoch]

PTAL