Play Framework

fix(observability): collapse status displays to VT-only output

Step 2/5 toward VT-only. PlayStatusPlugin and JobsPlugin's status text/JSON
no longer branch on isUsingVirtualThreads — both render the VT-mode shape
unconditionally. The ScheduledThreadPoolExecutor pool-size/active-count/
queue-size lines (platform-mode only) are gone; Invoker's inflight + total
counters remain in PlayStatusPlugin for both text and JSON.

JobsPlugin also drops the "Waiting jobs" section that walked the platform
STPE's queue via Java.extractUnderlyingCallable — that queue belongs to the
inner scheduler of VirtualThreadScheduledExecutor and contains short-lived
dispatch lambdas, not user-visible job objects, so the section would have
been misleading under the new architecture. The unused Java import is
removed.

ant test passes.

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