add a compat enabled date for fetchIterableTypeSupport

[vicb]

Make fetchIterableTypeSupport enabled by default from 2026-02-19.

Note that fetchIterableTypeSupportOverrideAdjustment will also be enabled by default from that date because it has

workerd/src/workerd/io/compatibility-date.capnp

Line 1262 in a89ad60

$impliedByAfterDate(name = "fetchIterableTypeSupport", date = "2026-01-15");

Some more details about this PR:

When we tried to enable the native node:process v2, we ran into issue because it caused astro to detect the workerd runtime as if it was Node and triggering a known issue in the code path it would then take.

Our plan is to make sure both fetchIterableTypeSupport and fetchIterableTypeSupportOverrideAdjustment are enabled before enabling node:process.

This is detailed in this workers-sdk issue. Please read it, ask questions, and give feedback.

/cc @danlapid @jasnell @guybedford

[github-actions]

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

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will degrade performance by 18.38%

_{Comparing vicb/fetchIterableTypeSupport (e3b80b9) with main (c9203d3)}

Summary

❌ 1 regressed benchmark
✅ 69 untouched benchmarks
⏩ 129 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	jsonResponse[Response]	34.8 µs	42.7 µs	-18.38%

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. ↩

[vicb]

Thanks for the reviews!