Limit proxy BEP named set events

[karim-alweheshy]

Summary

• Split large BEP named sets at 256 file entries for proxy-enabled builds.
• Filter the transport-only option from aquery replay and publishable invocation receipts.

Stack

• Depends on Support nested project paths in proxy manifests #3332.
• Pairs with XCBBuildServiceProxyKit fork PR Add Target and Generator.processTargetMerges() #12.

Validation

• Focused launcher test passed uncached on Bazel 9.2.0.
• Bash syntax, scoped ShellCheck, Buildifier, and diff checks passed.
• RedditApp final BEP was 3.4 MB with a maximum line size of 151.2 KB; Xcode build succeeded.

Testing

Run bazel --ignore_all_rc_files test //test/internal/build_proxy_launcher:build_proxy_launcher_tests.