* improvement (core): Model local definition with interfaces

[dkimitsa]

What does this PR address? (Why)

Expose original JVM variable slots and distinguish operand-stack temporaries for downstream analyses and code generation, preserving metadata during local transformations.

What are the main implementation details? (What, How)

• Make Local and JavaLocal interfaces, with shared AbstractLocal behavior and composable slot/stack and Java annotation variants.
• Add newSlotLocal and newStackLocal factories with private implementations and metadata-preserving withers; migrate constructor calls.
• Record provenance during bytecode conversion and preserve it during renaming and serialization; add slot, wide-parameter, and transformation tests.

Validation: clean core, Java core, interceptor, and both frontend suites (786 passed, 14 skipped); formatting passed.

Linked issue (if any)

None.

Checklist

Code style & guidelines

• I ran the formatter: mvn com.spotify.fmt:fmt-maven-plugin:format
• I added the necessary comments in the code
• I provided meaningful tests for my proposed change
• I updated documentation (if needed)

Self-review

• I performed a self-review of my code
• I added or updated tests where needed
• I have successfully run tests with my changes locally
• My branch is up to date with develop

Review

• CI checks are green
• I requested a review from a core contributor