Plan Measure v2.7.1

Improvements and fixes

• Reject markedly diagonal X/Y references when creating, recalibrating, or editing scales, and clarify that reference distances are measured along their axes while preserving saved calibration results. (#177)
• Allowed subsequent project reads and saves to reopen IndexedDB after an unexpected connection termination instead of repeatedly using a closed connection. (#181)
• Added recovery actions when autosave fails: retry saving, export the current project, or reload saved projects after confirmation, while preserving unsaved work in memory. (#182)
• Keep autosave recoverable when undoing a historical measurement or classification repair: pause while the restored data is invalid and resume automatically after repairing it or using Redo. (#180)
• Speed up large polygon validation so existing projects with many vertices can import and reopen more quickly without new size limits or changes to their geometry. (#178)

Validation

• Automated tests, lint and production build passed.
• GitHub Pages deployment verified for c383a9f.
• Workflow run.