Fix remaining format 1 conformance gaps

[fruwe]

Closes #61

Summary

• update the immutable format-1 conformance pin and harness to the merged 88-case authority
• preserve recorded holder lifetime associations when a bound reference is cleared or reused
• recursively reject non-finite programmatic values and normalize nested negative zero without changing int/double distinctions
• normalize reserved env.changed values before guards and handlers observe them

Validation

• ruff check .
• mypy src/determa
• pytest -q (175 passed)
• pinned conformance at ffbc65cbce49733803119a7dabf02a9727819ba8 against spec 4bd4d9588d11b75d376380b6120676a056a4bc45 (93 passed across 88 case directories)
• git diff --check

Scope

• package version remains 0.0.6
• no snapshot or hot-swap, package import, tutorial, CLI, release, tag, or unrelated workflow modernization work