chore(release): prepare v0.21.0

[benvinegar]

Summary

• exit the 0.21 prerelease train and version hunkdiff as 0.21.0
• consume the accumulated 0.21 Changesets and generate the stable changelog projection
• add hand-authored 0.21 release-page summary, tagline, and documentation links
• commit an 11-sample stable release benchmark snapshot

The runtime is unchanged from 0.21.0-beta.1; main added only release-page metadata and the website comparison pages after that tag.

Benchmark

bun run bench:release:compare passes against 0.20.1. The snapshot carries the previously approved wrapped-CJK mount exception: the controlled Firecracker A/B measured only +7.21ms/+5.3%, and this stable snapshot is effectively unchanged from beta.1 (90.52ms versus 91.21ms).

Validation

• bun run format:check
• bun run lint
• bun run typecheck
• bun run deps:check
• bun run check:docs
• bun run check:changelog
• bun run test
• bun run test:integration
• bun run test:tty-smoke
• bun run test:session-broker-node
• bun run check:pack
• bun run build:prebuilt:npm
• bun run check:prebuilt-pack
• bun run smoke:prebuilt-install
• bun run website:check
• bun run website:build
• bun run website:links
• bun run website:test:browser
• real 140×40 tmux TTY smoke on the compiled 0.21.0 binary
• full Firecracker install compatibility suite: 15/15 scenarios passed and release evidence validated

Firecracker result SHA-256: da628843eff6b62320f1d8a2a37e8ff0c09bcdc07928c2738aae3ef8efeeb1fc
Validated source identity: 655ceddd7c88839485e74cdc75166881349f56593dea8818f5dfaeb42ecab031

Release scope

Publishing v0.21.0 will advance npm latest and GitHub Latest. No tag or publication is part of this PR. Previously identified Windows ownership/reparse validation, reconnect-key rotation, and operational upgrade/rollback hardening remain follow-up work accepted for this release preparation.

This PR description was generated by Pi using gpt-5.6-sol

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Project	Deployment	Actions	Updated
hunk-web	Ready	Preview	Sep 2, 2026 1:39pm UTC

[benvinegar]

@greptile-apps please review this stable release-preparation diff. Focus on the prerelease exit, generated version/changelog state, retained empty Changeset, editorial website metadata, and benchmark exception continuity.

This comment was generated by Pi using gpt-5.6-sol

[greptile-apps]

Greptile Summary

This PR exits the 0.21 prerelease train and prepares the stable 0.21.0 release without changing runtime code.

• Sets hunkdiff to 0.21.0, removes prerelease state, consumes the accumulated Changesets, and generates the stable changelog projection.
• Adds editorial release metadata and regenerates the pre-tag website changelog, cards, and RSS state.
• Adds the 11-sample stable benchmark snapshot while retaining the documented wrapped-CJK exception.

Confidence Score: 5/5

The release-preparation PR appears safe to merge, with version, changelog, website publication state, and benchmark exception continuity aligned.

The stable package version and consumed prerelease state are coherent; generated website output intentionally keeps 0.21.0 unreleased until a tag supplies its publication date, and the benchmark snapshot follows established provenance and exception conventions.

Important Files Changed

Filename	Overview
package.json	Advances the package version from 0.21.0-beta.1 to the stable 0.21.0 version.
CHANGELOG.md	Adds the generated stable 0.21.0 projection while preserving the prior prerelease entries.
benchmarks/release/bench-0.21.0.json	Records an 11-sample stable benchmark snapshot and carries forward the documented wrapped-CJK exception consistently with beta.1.
website/releases/notes.json	Adds the hand-authored 0.21 summary, tagline, and related documentation links used by changelog generation.
website/src/content/docs/changelog/0.21.md	Correctly represents the undated stable release as unreleased while retaining prerelease publication metadata until tagging.
website/releases/cards.json	Regenerates the 0.21 card for the pre-tag state, excluding the unpublished stable version from published-version chips.
website/public/changelog/rss.xml	Updates editorial descriptions without prematurely publishing an RSS item for the undated stable release.

_{Reviews (1): Last reviewed commit: "chore(release): prepare v0.21.0" | Re-trigger Greptile}