Finalize changelog for 0.3.18

[TheGreatAxios]

Summary

• Publishes Corbits Code 0.3.18 release notes from merged work since v0.3.17.
• Dates the 0.3.18 changelog section for the release.

Verification

• bun run check passes.
• Notes reconcile against v0.3.17..origin/main and all 13 Linear v0.3.18 issues.

[TheGreatAxios]

Critic · Request changes

Publishes the 0.3.18 changelog from the merged release range.

Findings

• CHANGELOG.md:34 — The note says both row and chrome updates are coalesced to renderer cadence, but only row updates are frame-coalesced (src/tui/row-update-queue.ts:1); chrome recomposes synchronously whenever its input key changes (src/tui/shell/chrome.ts:186). Multiple chrome input changes before one renderer frame therefore trigger multiple recompositions, so split this into the two behaviors implemented by the PR.

Notes

• The release header, one-file scope, 13 release concepts, and release-script section matcher otherwise reconcile with v0.3.17..origin/main and merged PRs #819-#833.