refactor(generators): use Map.groupBy in groupNodesByModule

[btea]

Description

Replaces the hand-rolled Map grouping loop in groupNodesByModule with the native Map.groupBy() static method. It groups an iterable by the value returned from a callback, which is semantically identical to the previous implementation — a behavior-neutral simplification that reduces boilerplate and improves readability.

Map.groupBy() requires Node.js ≥ 21 (V8 12.0); the project's .nvmrc pins Node 24, so this is safe.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/groupBy

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Check List

• I have read the Contributing Guidelines and made commit messages that follow the guideline.
• I have run node --run test and all tests passed.
• I have check code formatting with node --run format & node --run lint.
• I've covered new added functionality with unit tests if necessary.

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Project	Deployment	Actions	Updated (UTC)
api-docs-tooling	Ready	Preview	Jul 29, 2026 1:32pm

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[cursor]

PR Summary

Low Risk
Behavior-neutral refactor of a small utility; callers still receive a Map keyed by module name.

Overview
groupNodesByModule now uses the native Map.groupBy() static instead of manually iterating nodes and pushing into a Map.

Grouping is still keyed by each entry’s api field, so callers that use .get(head.api) (e.g. JSX and legacy HTML generators) should see the same shape and behavior with less boilerplate. This relies on Map.groupBy, which needs a recent Node runtime (project targets Node 24).

^{Reviewed by Cursor Bugbot for commit 48f85db. Bugbot is set up for automated code reviews on this repo. Configure here.}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.51%. Comparing base (9ab2840) to head (48f85db).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #956      +/-   ##
==========================================
- Coverage   86.52%   86.51%   -0.01%     
==========================================
  Files         195      195              
  Lines       17974    17963      -11     
  Branches     1633     1632       -1     
==========================================
- Hits        15552    15541      -11     
  Misses       2416     2416              
  Partials        6        6              

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