v0.20.0

What's Changed

• docs: add the polako loop infographic to the README by @scharissis in #317
• docs: record why the frozen CI build cache stays frozen by @scharissis in #315
• feat: the review gate can be cheaper than "medium" on a small diff by @scharissis in #319 (closes #255)
• docs: add VISION.md and the plan-conventions plan by @scharissis in #320
• feat: default -max-issue-time to 45m instead of unbounded by @scharissis in #328 (closes #256)
• feat: stats -by reason by @scharissis in #329 (closes #257)
• test: share one git fixture across upstream() callers by @scharissis in #330 (closes #316)
• feat: skill-change runs let the eval suite run itself by @scharissis in #331 (closes #311)
• docs: fold every plan document into one docs/plans/ directory by @scharissis in #332 (closes #322)
• feat: parse the plan footer out of an issue body by @scharissis in #333 (closes #323)
• feat: status gains a plans section derived from issue footers by @scharissis in #334 (closes #324)
• feat: a closed epic files a retire issue for its plan document by @scharissis in #335 (closes #325)
• docs: the plan-document convention travels with plan-backlog by @scharissis in #336 (closes #326)
• docs: triage the surviving plan documents by @scharissis in #337 (closes #327)

Full Changelog: v0.19.1...v0.20.0