Migrate SQLCommenterTest from Groovy/Spock to JUnit 5 Java (#11735)

Migrate SQLCommenterTest from Groovy/Spock to JUnit 5 Java

Faithful 1:1 migration of the jdbc SQLCommenterTest: all 91 cases preserved
(8 getFirstWord + 68 inject + 12 base-hash + 3 peer-service). Spock `where:`
tables become @ParameterizedTest + @MethodSource (the data carries embedded
quotes, whitespace-significant, and null cells that @TableTest can't represent),
each row led by a human-readable scenario for the display name. Config injection
uses the imperative WithConfigExtension.injectSysConfig (values are parameterized).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Merge branch 'master' into dougqh/migrate-sqlcommenter-test

Make the redundant optimizer-hint case a real idempotency test

The migration faithfully copied a duplicate row that already existed in the Groovy
(two identical leading-hint append cases). Per review, repurpose it to verify the
intended behavior: re-injecting already-commented SQL is a no-op (hasDDComment skips it).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Merge branch 'master' into dougqh/migrate-sqlcommenter-test

Co-authored-by: devflow.devflow-routing-intake <devflow.devflow-routing-intake@kubernetes.us1.ddbuild.io>

Author: dougqh