Recompile when dependencies change

[wilx]

Summary

• persist the ordered class path and module path in the plugin-local dependencies.lst state file
• collect persisted metadata and the current-build timestamp fallback in one cached scan per normalized dependency path, removing the previous duplicate traversal
• record regular dependency files as size and modification time, and exploded dependency directories as a stable metadata fingerprint
• trigger the existing changed dependency rebuild reason when dependencies are added, removed, reordered, relocated, or replaced at the same path
• add unit coverage for the consolidated detector and integration coverage for dependency removal and same-path SNAPSHOT replacement

Why

The 3.x incremental check only considered dependency timestamps relative to the current Maven session. It could therefore miss a dependency removed between invocations or a JAR replaced at the same path before the next invocation, leaving stale application bytecode.

The persisted comparison and the existing session-relative fallback are now consolidated. A missing baseline still detects dependencies rebuilt during the current Maven invocation, while unchanged builds no longer walk exploded dependencies once for persisted state and again for the timestamp fallback.

Validation

• JAVA_HOME=/opt/jdks/latest-8 /opt/maven/latest/bin/mvn clean verify — 36 tests passed
• JAVA_HOME=/opt/jdks/latest-21 /opt/maven/latest/bin/mvn clean verify — 36 tests passed
• focused MCOMPILER-349, MCOMPILER-474, dependency-removal, and same-path-replacement integration tests passed
• JAVA_HOME=/opt/jdks/latest-21 /opt/maven/latest/bin/mvn -Prun-its clean verify — 78 builds passed, 5 environment-specific skips

Fixes #1087

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Following this checklist to help us incorporate your
contribution quickly and easily:

• An issue is filed for this change: No recompilation if the dependencies have changed #1087. This pull request addresses only that issue.
• Each commit in the pull request has a meaningful subject line and body.
• The pull request title describes the issue. The template's [MCOMPILER-XXX] convention is not applicable because this is tracked as GitHub issue No recompilation if the dependencies have changed #1087.
• The pull request description explains what the pull request does, how, and why.
• Ran mvn clean verify.
• Ran the integration tests successfully with mvn -Prun-its clean verify.

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