Warning: This build has drifted.
The coverage report for this pull request build may be inaccurate because its base commit is no longer the HEAD of its target branch.
This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

    • Learn more: For more information on this, see Tracking coverage changes for pull request builds.
    • Fix now: For a quick fix, rebase this PR at GitHub. Your next report should be accurate.
    • Prevent going forward: To avoid this issue with future PRs, see these Recommended CI Configurations.

refactor: improve code quality and test coverage

Encoder refactoring:
- Refactor arrays.ex with pattern-matched clauses for composability
- Refactor objects.ex with pattern-matched encode_regular_entry/encode_folded_value
- Rename predicates to follow Elixir conventions (tabular_array?, list_array?)
- Extract reusable helpers (apply_marker, build_*_line functions)

Decoder refactoring:
- Remove Process dictionary anti-pattern from structural_parser.ex
- Thread metadata explicitly through all parsing functions
- Add key_was_quoted? and add_key_to_metadata helpers
- Clean up parser.ex by removing Process.put/get calls

Test improvements:
- Add decode/options_test.exs with 23 tests (100% coverage)
- Add encode/options_test.exs with 25 tests (100% coverage)
- Expand encoder_test.exs from 4 to 23 tests (65% coverage)
- Add test fixtures: UserWithOnly, StructWithoutEncoder
- Strengthen assertions with specific error.value checks

Total: 511 tests, 83.5% coverage, all quality checks pass.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>