Fix RenderWorkflow() handler (was a stub that never loaded data), remove dead chat UI from workflow.html, align stage mode naming with Go constants, add 17 SQLite store tests, decompose 400-line InstallPackage into 7 phases, add E2E workflow-without-chat test. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>