Verify the 4.0.0 release criteria and prepare free publication

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Outcome

Make a 4.0.0 release decision from verified evidence: increased performance and coverage, reduced allocations, no known unresolved bugs, completed research verdicts, reviewed adoption/docs, and zero open issues at readiness. Asset Store publication follows readiness through the existing operator checklist.

Release criteria

• All current research issues receive actual investigations and retained verdicts. A rejected mechanism or demonstrated infeasibility counts; unattempted work does not.
• Research MessagePipe performance targets and formal parity for 4.0.0 #414 reports all six target rows against MessagePipe. Aim for at least 80% throughput per row; documented residual gaps may remain after the agreed research completes. Preserve the 90% lower-confidence-bound formal parity criterion. Do not average away failed rows.
• Confirm performance improvements against the frozen baseline with perf lab: calibrate variance, controls, power, and confirmatory inference #510, preserve affected routes and sentinels, and retain zero-allocation steady-state dispatch. Report registration allocations and retained memory separately.
• Close correctness, coverage, adoption, and documentation tasks with linked evidence and maintainer review.
• Pass full supported Unity correctness, explicit allocations, shipping/stripping/AOT consumers, generator/analyzer, scripts, docs, package validation, install and sample checks at the final release revision.
• Prepare 4.0.0 metadata, release notes, migration guide, exact package artifacts, checksums, screenshots, and store collateral through existing release tooling. Do not bump to the final release early.
• Audit all remaining open issues and close this readiness issue last when its criteria pass. New unresolved defects reopen readiness. Do not close an issue solely to reach a count.

Publication handoff

After readiness, run the existing release workflow and official manual Asset Store upload. Keep MIT in the repository/package and verify applicable storefront terms. Use admitted UPM publishing or the existing classic export. Price stays Free (USD 0), with no paid editions, upgrades, or feature charges. Verify the live version, price, disclosure, links, screenshots, and clean installation. Record publication in the operator tracker defined by the runbook.

Working constraints

No deadline, hardware purchases, or paid research services are assumed. Use existing tooling. External account access, store review, and #521's repository-wide immutable-release approval are explicit dependencies. Prepare concrete reviewable inputs before requesting any required approval.