Release v0.2.8

[tjgreen42]

Tracking issue for the v0.2.8 release. Procedure: prompts/pg_durable-release.md.

Cut line (PRs in this release): #371, #370, #367, #373, #378, #377, #385
Tag commit: pending merge of #385
Published by: pending approval

• Cut line confirmed
• Changelog merged (Prepare release v0.2.8 #385)
• Version/upgrade-script sanity
• CI green on tag commit ()
• Tagged v0.2.8 → draft Release (run #…, release: …)
• Release published (approved by: …)
• GHCR images confirmed (run #…)
• PGXN release confirmed
• Next-cycle PR opened (#…)