feat: add access context types

[BSFishy]

Replaces #6413 and #6549.

Adds types for Cloudflare Access integration into Workers

[codecov-commenter]

Codecov Report

❌ Patch coverage is 37.93103% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.61%. Comparing base (ac31559) to head (55e36f9).

Files with missing lines	Patch %	Lines
src/workerd/api/global-scope.c++	19.04%	15 Missing and 2 partials ⚠️
src/workerd/api/global-scope.h	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6735      +/-   ##
==========================================
- Coverage   66.62%   66.61%   -0.01%     
==========================================
  Files         402      402              
  Lines      115914   115937      +23     
  Branches    19425    19428       +3     
==========================================
+ Hits        77226    77230       +4     
- Misses      27095    27111      +16     
- Partials    11593    11596       +3     

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[petebacondarwin]

Feels like we need to run the snapshots against clean main to remove the extra unexpected types?

[codspeed-hq]

Merging this PR will improve performance by 13.76%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 71 untouched benchmarks
⏩ 129 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	Encode_ASCII_256[TextEncoder][0/0/256]	3.1 ms	2.7 ms	+13.76%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing BSFishy:add-access-types (822a381) with main (ac31559)}

Footnotes

1. 129 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. ↩

[petebacondarwin]

Reviewed for typings