* Lower AbortController for fetch cancellation
- Add static and dynamic lowering for construction, signal access, and abort calls
- Back controllers with native signal state shared by fetch
- Cover cancellation semantics across C, LLVM, diagnostics, and surface tests
Co-authored-by: sensei-woo <sensei-woo@users.noreply.github.com>
* Fix AbortController abort edge cases
* Fence AbortController method extraction
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Co-authored-by: sensei-woo <sensei-woo@users.noreply.github.com>
