fix(kmir): preserve symbolic parallel proving server selection

[Stevengre]

Summary

• keep symbolic prove-rs on the Haskell-only path (KompiledSymbolic.llvm_lib_dir=None) while preserving parallel exploration by selecting KoreServer when no LLVM library is available
• keep booster execution for LLVM-backed runs and pass KMIR_HS_ONLY_SYMBOLS through --hs-only-symbol flags when booster is used
• add unit coverage for the no-LLVM parallel path (test_prove_parallel_uses_kore_server_without_llvm_library)
• remove unused kompile.py symbols/locals that were failing flake8 in CI

Context

This branch rebases the PR853 experiment onto master and focuses on the symbolic-proof server selection mismatch on the rebased head.

Implementation Notes

• _prove_parallel() now builds common server args once, then chooses BoosterServer only when llvm_library_dir exists, otherwise KoreServer.
• HS-only booster command wiring remains limited to the booster path.
• Type hints/casts were added in _prove.py and the new unit test so mypy passes under make check.

Testing

Automated checks run:

• make check (passed)
• uv run pytest -q src/tests/unit (passed, 42 passed)

Manual/targeted checks:

• uv run pytest -q src/tests/integration/test_cli.py::test_cli_prove_rs_add_module (not passed locally: missing /Users/steven/.cache/kdist-21d0fbc/mir-semantics/haskell fixture directory)

Known Limitations / Follow-ups

• Local integration execution in this worktree remains unsure until required kdist artifacts are available; rely on CI integration jobs for full integration validation.

[Stevengre]

Added TDD-structured follow-up commits for HS-only booster wiring:\n\n- test(kmir): add hs-only symbol env wiring unit tests\n- feat(kmir): pass KMIR_HS_ONLY_SYMBOLS to kore-rpc-booster\n\nRed/green evidence:\n- Red: -> 3 AttributeError failures before wiring\n- Green: same command -> 3 passed after wiring

[Stevengre]

Correction with exact refs:\n\nAdded TDD-structured follow-up commits for HS-only booster wiring:\n- 0f208ed: test(kmir): add hs-only symbol env wiring unit tests\n- 6ef9fc9: feat(kmir): pass KMIR_HS_ONLY_SYMBOLS to kore-rpc-booster\n\nRed/green evidence command:\nuv --project kmir run -- pytest kmir/src/tests/unit/test_kmir_hs_only_symbols.py -q\n- red (before wiring): 3 AttributeError failures\n- green (after wiring): 3 passed