feat(ledger): count acquisition stalls instead of only logging them

A saturated ledgerData lane makes TimeoutCounter re-arm its timer
without running the timer body, so timeouts_ never advances and the
six-timeout give-up can never fire. Acquisitions then neither finish
nor fail until the one-minute sweep destroys their partial maps, and
the work restarts. Every step of that chain was debug-log-only, so a
node at warning level could not be diagnosed after the fact.

The counters are separate on purpose: deferrals rising while timeouts
stay flat is the signature, and no single counter shows it.

Completions are recorded in done() rather than at the "Done: complete"
log line, because that line also fires for failures and misses the
checkLocal and receiveNode paths; done() is the one funnel every
outcome passes through and its signaled_ guard makes it idempotent.

AcquireStats is only forward-declared in ServiceRegistry so libxrpl
still includes nothing from xrpld. The src/ include path for the test
binary moves out of the telemetry guard, since a header-only type
under src/xrpld/ is testable in every build.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.github/scripts/levelization/results/ordering.txt

@@ -190,6 +190,7 @@ tests.libxrpl > xrpl.basics
 tests.libxrpl > xrpl.config
 tests.libxrpl > xrpl.consensus
 tests.libxrpl > xrpl.core
+tests.libxrpl > xrpld.app
 tests.libxrpl > xrpld.telemetry
 tests.libxrpl > xrpl.json
 tests.libxrpl > xrpl.ledger