Harden distributed coordination for DataProvider 3.4.2

[remdui]

Summary

Prepares DataProvider 3.4.2 as the qualified coordination foundation for later FeatureFramework replica-group work without adding any application-specific clustering API.

Changes

• align DataProvider with haunted-library-parent 1.5.0 and prepare release version/tag metadata for 3.4.2
• remove Maven plugin/version declarations now inherited from HauntedPlatform while retaining DataProvider-specific coverage, duplicate-class, and Mockito/JDK 25 settings
• make the inherited Mockito version a proper Surefire plugin dependency so the JDK 25 test agent is resolved before forked test JVMs start
• add dedicated Redis/Testcontainers integration coverage for exact lease ownership, renewal, release, process-incarnation ownership, strict fencing-token monotonicity, forced claim takeover, stale writer/delete rejection, and reconnect-after-expiry behavior
• document the generic distributed-coordination contract, including recommended <logical-node-id>/<process-id> owners and the difference between acquire and claim
• update README/package examples to 3.4.2

Deliberately not included

• no ClusterService, replica-group, leader-selection, or FeatureFramework-specific API
• no new DataProvider configuration sections
• no cluster-generation persistence
• no redesign of the existing CoordinationDataAccess API

Validation

CI runs normal unit/integration/coverage, shared Maven-policy validation, ShellCheck, and bundled Paper/Velocity platform acceptance. The new RedisCoordinationFencingIT is exercised by the existing integration-tests profile with Docker/Testcontainers.

The first CI run exposed a real HauntedPlatform-1.5 alignment issue: DataProvider's Surefire -javaagent path referenced the inherited Mockito version before that artifact was guaranteed to be resolved in modules that do not directly depend on Mockito. The PR now declares Mockito as a Surefire plugin dependency, preserving the existing agent model without pinning an obsolete version.

Commit structure

1. chore(build): align DataProvider 3.4.2 with HauntedPlatform 1.5
2. test(coordination): qualify fenced lease semantics
3. docs(coordination): document fenced lease semantics
4. docs: add distributed coordination guide to index
5. docs(release): prepare DataProvider 3.4.2 documentation
6. chore(build): inherit shared Maven policy from HauntedPlatform
7. fix(build): resolve Mockito agent through Surefire