v1.20260918.1

What's Changed

• Keep native pipes from consuming a destination with pending writes by @jasnell in #7395
• Stop identity stream aborts from waiting for a read by @jasnell in #7399
• Wire the Rust I/O backend into workerd: --//:io_backend, on by default by @danlapid in #7328
• Fix container startup flags after cancellation by @jtolio in #7402
• Add a ring buffer for the streams' internal queues by @jasnell in #7405
• Clean up containers on graceful shutdown by @ghostwriternr in #7244
• Move retry claim before actor construction by @apeacock1991 in #7230
• Add just format <files>, just format-head by @sohpeach in #7407
• Abstract CrossThreadWaitList into SyncWaitList and introduce XThreadWaitList by @ObsidianMinor in #7397
• update capnproto by @mikea in #7400
• Improve TS stream primordial safety by @jasnell in #7409
• fix compile_flags.txt by @mikea in #7415
• Updates v8 to 15.4 by @dom96 in #7386
• update capnproto by @mikea in #7420
• Implement inbound UDP handler by @ThomasRubini in #7130
• Add coroutine-hostile-raii lint for UnwindDetector, and add fixes by @jtolio in #7153

Full Changelog: v1.20260917.1...v1.20260918.1