Preserve .agent-no-read.md in Java runtime source and installed artifacts #270

Parent: teaql/teaql-conformance#235. Audit runtime implementation roots, package filters and actual local candidate install/extraction. Maintain .agent-no-read.md deterministically with the existing Agent Context Kit maintenance protocol or native packaging propagation, preserve dotfiles in source/binary package formats where ordinary files are supported, and document precise unsupported expansion/Bash boundaries. Keep README/public API guidance/Assist outside exclusions. Never mark a mixed application root or modify shared package caches. Add focused producer/package/install and policy tests with retained per-language evidence; unverified formats are not support claims. No public release, version tag, deployment or unrelated behavioral changes.