perf: use slf4j placeholders instead of string interpolation in logging

[pjfanning]

Motivation

Several slf4j log calls in main sources built their message with Scala string interpolation, so the message was formatted eagerly even when the level was disabled. A few others carried an s prefix on a literal with no interpolation at all, which is misleading next to the {} placeholders in the same string.

Modification

• Replaced interpolated log messages with slf4j {} placeholders and lazily formatted arguments in persistence-typed BehaviorSetup (both the event-sourced and durable-state variants), EventSourcedBehaviorImpl, and the testkit LogCapturing / LogCapturingExtension rules.
• Dropped the redundant s prefix from log literals that contain no interpolation in Running and RequestingRecoveryPermit (both variants).
• BehaviorSetup.onSignal now passes the signal as a placeholder argument and keeps the throwable as the trailing slf4j argument, so the stack trace is still logged without rendering the exception into the message eagerly.

Result

Log message rendering is deferred to the logging backend and only happens when the level is enabled. Rendered output is unchanged apart from onSignal, where the exception toString is no longer duplicated in the message text; it remains available via the logged throwable.

Tests

• sbt "actor-testkit-typed/compile" "persistence-typed/compile" - pass
• scalafmt on changed files - pass
• No behaviour change beyond log formatting; existing EventSourcedBehaviorLoggingSpec assertions on "Handled command" cover the unchanged message text. Full test run left to CI.

References

None - internal logging cleanup