fix(parser): correct label-too-long error position

[tigerwill90]

1. parseHostname's "label exceeds 63 characters" error reported the wrong start offset when the offending label contained a parameter, because the position was reconstructed from i - partLen while parseBrace advances i without touching partLen
2. parseBrace also silently accepted ASCII control bytes and DEL inside parameter names, which is now rejected to match the existing check on path bodies.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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