module: cache deserialized package scopes

[gurgunday]

ESM loading repeatedly deserializes the same package configuration when resolving package imports and determining the format of relative .js imports. Spreading the configuration invokes its lazy getters, reparsing the imports and exports maps on each lookup

Cache the deserialized configuration by package.json path and reuse it when the serialized fields are unchanged. Each lookup still calls the existing loader method, so live VFS changes and errors remain visible. VFS unmounting clears the cache, and callers continue to receive separate result wrappers.

                                                     confidence   improvement   accuracy (*)    (**)   (***)
module/package-scope-config.js n=10000 entries=0     ***            +83.33 %   ±3.12%  ±4.34%  ±6.08%
module/package-scope-config.js n=10000 entries=20    ***           +207.93 %   ±5.72%  ±8.03%  ±11.37%
module/package-scope-config.js n=10000 entries=200   ***          +2494.96 %   ±59.83%  ±85.90%  ±126.23%
module/package-scope-config.js n=10000 entries=1000  ***          +3577.25 %   ±67.32%  ±96.71%  ±142.26%

Measured on an Apple M5 Pro. Inspired by/continues the work of #60425.

[nodejs-github-bot]

Review requested:

• @nodejs/loaders
• @nodejs/performance

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.18%. Comparing base (ad67159) to head (06b6f9a).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65812      +/-   ##
==========================================
+ Coverage   90.14%   90.18%   +0.03%     
==========================================
  Files         769      770       +1     
  Lines      262968   264430    +1462     
  Branches    50060    50241     +181     
==========================================
+ Hits       237057   238466    +1409     
- Misses      16932    16973      +41     
- Partials     8979     8991      +12     

Files with missing lines	Coverage Δ
lib/internal/modules/package_json_reader.js	99.31% <100.00%> (+0.03%)	⬆️

... and 30 files with indirect coverage changes

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