fix(error): guard org.springframework.dao instanceof checks behind a classpath flag

[casc84ab]

Problem

ExceptionMetadataAspect (@Aspect @Component @Order(1), always registered) runs for every exception via @Around on ExceptionConverterService.convertException. It used hard checks:

if (exception instanceof org.springframework.dao.DataIntegrityViolationException) { ... }
else if (exception instanceof org.springframework.dao.QueryTimeoutException) { ... }

Those classes ship with spring-tx (pulled transitively by spring-data). fireflyframework-web declares spring-data-commons as optional, so data-less services (e.g. reactive BFFs without a DB) run without spring-tx on the classpath. There, the instanceof forces class resolution at runtime and throws NoClassDefFoundError: org/springframework/dao/DataIntegrityViolationException while building exception metadata — breaking the reactive error path: downstream errors surfaced as hangs/timeouts instead of clean 5xx responses.

This was latent and got exposed when services migrated off the old IdP stack (which dragged spring-tx in transitively) to the new fireflyframework-security-* modules.

Fix

Gate both checks behind a static flag and rely on && short-circuit:

private static final boolean SPRING_DAO_PRESENT = ClassUtils.isPresent(
        "org.springframework.dao.DataIntegrityViolationException",
        ExceptionMetadataAspect.class.getClassLoader());
...
if (SPRING_DAO_PRESENT && exception instanceof org.springframework.dao.DataIntegrityViolationException) { ... }
else if (SPRING_DAO_PRESENT && exception instanceof org.springframework.dao.QueryTimeoutException) { ... }

• Absent (BFF / data-less): the && short-circuits, the instanceof (and its class resolution) is never reached → no NoClassDefFoundError.
• Present (services with a DB): the instanceof runs unchanged, still matching the full subclass hierarchy (e.g. DuplicateKeyException) → existing behavior fully preserved.

This aligns the always-on aspect with the converters that already use @ConditionalOnClass for the same spring-dao types.

Verification

• Compiles; bytecode confirms getstatic SPRING_DAO_PRESENT short-circuits before the instanceof.
• Runtime: a reactive BFF (no spring-tx) calling a downed downstream now returns HTTP 503 in ~0.26s with zero NoClassDefFoundError (previously a 20s hang / empty reply).
• Core services (with spring-tx) keep identical data-integrity / query-timeout metadata, subclasses included.