CAS v3.27.4

• Merge pull request #943 from Richards-LLC/release/v3.27.4
• release: prepare v3.27.4
• docs(release): user thread in product wording (announce lint)
• docs(release): 3.27.4 changelog section and announcement draft
• Merge pull request #942 from Richards-LLC/factory/fair-lark-93
• Merge pull request #941 from Richards-LLC/factory/calm-octopus-51
• fix: wake workers when delivery PRs merge
• fix(cas-ec94): scan lib tests for checkout reads
• Merge pull request #940 from Richards-LLC/factory/quick-finch-11
• Merge pull request #937 from Richards-LLC/factory/wise-kestrel-52
• fix(release): close release train cut gaps
• fix(cas-ca81): cache scoped proof resolution per close
• test(release): cover tonight's train gaps
• fix(cas-ca81): resolve scoped checker at runtime
• Merge pull request #939 from Richards-LLC/factory/calm-octopus-51
• Merge pull request #933 from Richards-LLC/factory/quick-finch-11
• fix worker guard during rebases
• fix(release): resolve standalone receipts stage imports
• Merge remote-tracking branch 'origin/main' into factory/quick-finch-11
• Merge pull request #938 from Richards-LLC/factory/fair-lark-93
• fix(cas-5fa56): ignore untracked factory metadata
• Merge pull request #936 from Richards-LLC/factory/calm-octopus-51
• fix(cas-ca81): share scoped proof target derivation
• fix(cas-5fa56): keep worker guidance within budget
• fix rolling sweep ancestor attribution
• docs(release): lint-clean v3.27.3 report
• Merge remote-tracking branch 'origin/main' into factory/quick-finch-11
• fix(cas-5fa56): reset reused factory branches on start
• Merge pull request #935 from Richards-LLC/docs/release-receipts-v3.27.3
• docs(release): record v3.27.3 receipts and report
• fix(release-train): carry receipts on release branches
• test(release-train): pin branch receipt handoff