feat(parser): mark pure comments that cannot be applied

[Boshen]

Summary

Adds CommentContent::PureNotApplied variant to flag #__PURE__ / @__PURE__ annotations that cannot be applied, aligning with Rollup's behavior for invalid pure comment positions.

Changes

• set_pure_on_call_or_new_expr now returns bool so callers detect when the annotation couldn't be applied
• Track the specific pure comment index (Option<usize>) instead of a boolean flag, fixing a bug where the wrong comment could be retagged when multiple pure comments exist (e.g. /*#__PURE__*/ foo + /*#__PURE__*/ bar())
• Mark pure comments as PureNotApplied in three contexts:
  • Expression-level: annotation not before a call/new expression (e.g. /* #__PURE__ */ a().b)
  • Statement-level: annotation before non-expression statements (e.g. /* #__PURE__ */ function foo() {})
  • Variable declarator: annotation before = (e.g. const foo /* #__PURE__ */ = bar())
• Downstream consumers (codegen, minifier, Rolldown) can check for PureNotApplied to warn or strip

Closes #20334

Rolldown will add custom logic to emit the comments that are PureNotApplied so it does not affect the rest of the compiler pipeline.

Test plan

• Unit tests for all PureNotApplied cases (expression, statement, variable declarator)
• Regression test for correct comment targeting with multiple pure comments
• Codegen integration tests updated
• cargo test -p oxc_parser -p oxc_codegen passes

🤖 Generated with Claude Code

[codspeed-hq]

Merging this PR will not alter performance

✅ 53 untouched benchmarks
⏩ 3 skipped benchmarks¹

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_{Comparing boshen/pure-comment-not-applied (5a821b7) with main (77abf54)}

Footnotes

1. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[chatgpt-codex-connector]

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[Dunqing]

Merge activity

• Mar 25, 12:57 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Mar 25, 12:57 AM UTC: Dunqing added this pull request to the Graphite merge queue.
• Mar 25, 1:01 AM UTC: Merged by the Graphite merge queue.