Make int32 config parsing strict and loud

[hbarthels]

Summary

_extract_value_int32 previously silently returned the field default when a config value was present but not an int32_value (e.g. a bare 2 written instead of 2i32). That silent fallback masked malformed input — the real bug was the silent failure, not strictness.

This changes the helper to error loudly (ParseError) when a config value is present with the wrong type, while:

• keeping the i32 suffix requirement (we do not promote bare ints), and
• returning the default only when the field is genuinely absent.

This is a fresh take on #265 addressing @comnik's review feedback: don't promote — error loudly on the wrong type.

Changes

• meta/src/meta/grammar.y: rewrote _extract_value_int32 — absent field → default; present int32_value → return it; present anything else → builtin.error(...). Emitted as a bare statement (the builtin.error template codegens to raise/throw/panic, which is invalid in a return position).
• Regenerated the Python, Julia, and Go parsers via make force-parsers. The bulk of the generated-file diff is temp-variable (_tNNNN) renumbering; the only logic change is _extract_value_int32. Go builds clean.
• Regression tests (Julia parser_tests.jl, Python test_parser.py): :csv_header_row 2i32 parses (header_row == 2); a bare 2 raises ParseError; omitting the field yields the default (1).

No version bump — that goes in its own separate PR.

Testing

• Python: 789 passed
• Julia: 174/174 test items, 33740 assertions pass
• Go: go test ./test/... and go build ./... pass

🤖 Generated with Claude Code