next.js

bbbc7914 - Cleanup: extract helpers, reduce duplication, restore idiomatic patterns

Cleanup: extract helpers, reduce duplication, restore idiomatic patterns - Extract `formatSourceCodeFrame` helper in format-issue.ts to deduplicate code-frame rendering between primary and additional sources - Extract `SourcePosition` type in types.ts to replace inline position objects - Improve comments and simplify `extractErrorBlock` in test file - Inline `source_ref()`/`with_source()` into `to_generated_code_source()` since they had no other callers - Restore `bail!` macro usage instead of `Err(anyhow!(...))` in Rust files - Fix `bail!(format!(...))` → `bail!(...)` and typo "need" → "needs"