Play Framework

chore(deps): drop commons-javaflow

Step 4/4 — finishes the Javaflow elimination. The dependency line in
dependencies.yml and the commons-javaflow-1590792.jar in framework/lib are
removed. No remaining source code in the framework, modules, or sample apps
imports any javaflow class; ant test (unit + integration + CLI) is green
without the jar on the classpath.

Net result of the four-commit pass:
- ~370 lines of source deleted
- 1 native jar removed
- 1 enhancer slot removed from the bytecode pipeline (every loaded application
  class now skips the StackRecorder bytecode rewrite)
- The await(...) family is now a straightforward Thread.sleep / future.get,
  preserving every ThreadLocal-bound resource across the wait

Operator-visible note: stale framework/test-src/integration/testapp/tmp/
directories cached pre-enhancement bytecode that referenced the (now-deleted)
EnhancedForContinuations marker. Existing checkouts of this branch will need
a one-time `rm -rf <app>/tmp` for any app whose tmp/ predates this commit;
fresh checkouts and CI are unaffected.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>