refactor(dependencies): move guava out of root <dependencies> into opt-in dependencyManagement #7608

Summary

The root pom.xml force-inherits com.google.guava:guava (compile scope) into every reactor module via the top-level <dependencies> block, even modules that never use it.

Evidence

• pom.xml:610 opens the root <dependencies> block.
• pom.xml:612-620 declares com.google.guava:guava (with com.google.re2j:re2j exclusion) inside that global block, alongside slf4j-api / jcl-over-slf4j / junit-jupiter / junit-vintage.
• Guava is the only non-logging / non-test compile dependency globally inherited here; it is not universally required.

Side effect: global inheritance bloats every module's classpath with Guava's (large) transitive tree and masks dependency:analyze "unused declared" warnings for modules that don't actually need it.

Action

1. Remove the guava <dependency> from root <dependencies> (pom.xml:611-620).
2. Keep guava centralized in root <dependencyManagement> (pom.xml:329-333) so the version stays managed.
3. Add an explicit <dependency>com.google.guava:guava</dependency> (version managed) only to the modules that actually import com.google.common.* (typically shenyu-admin, shenyu-common — verify with git grep com.google.common).
4. Per affected module, run mvn dependency:analyze to confirm no "Used undeclared" regressions after the change.

Acceptance

• No module inherits guava unintentionally.
• Explicit guava dependencies exist only where used.
• CI green.

Related

• [Cleanup] Remove the orphaned shenyu-registry-consul module left behind by the Consul externalization #7583 (dependency cleanup umbrella)