[build] Update to Bazel 9

[fhanau]

No description provided.

[github-actions]

The generated output of @cloudflare/workers-types matches the snapshot in types/generated-snapshot 🎉

[fhanau]

Managed to get this to work much earlier than expected 💪 Previous Bazel major releases have been relatively bug-prone – if this gains approval earlier I plan to not merge this until at least Friday to see if any major bugs surface until then.

[codspeed-hq]

Merging this PR will not alter performance

✅ 70 untouched benchmarks
⏩ 129 skipped benchmarks¹

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_{Comparing felix/012026-bazel9 (728b465) with main (752ea91)}

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. ↩

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.00%. Comparing base (752ea91) to head (728b465).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5937      +/-   ##
==========================================
+ Coverage   69.66%   70.00%   +0.33%     
==========================================
  Files         397      406       +9     
  Lines      105999   107106    +1107     
  Branches    17965    17965              
==========================================
+ Hits        73848    74979    +1131     
+ Misses      21358    21331      -27     
- Partials    10793    10796       +3     

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