Keep primitive list types on web

[Rexios80]

Summary

• On web, List<double>, List<bool>, and List<String> were stored as JS arrays and read back as List<Object?>, so a typed box threw on get after a reopen.
• Those lists are now stored with Hive type IDs.
• Values already saved as JS arrays still read as List<Object?> until they are written again.

Fixes #342

Test plan

• VM: typed primitive list tests
• Chrome dart2js and dart2wasm: those tests plus the web storage backend tests
• CI

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.72%. Comparing base (16adeda) to head (a13d69f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #343      +/-   ##
==========================================
+ Coverage   93.68%   93.72%   +0.03%     
==========================================
  Files          66       66              
  Lines        2678     2678              
==========================================
+ Hits         2509     2510       +1     
+ Misses        169      168       -1     

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