VS-13 Release Readiness (E2E Critical Flows + Docs + Bug Bash)

[CherryClairette]

What to build

Finalize release readiness by validating critical end-to-end flows, resolving top bugs from bug bash, and updating contributor documentation so new teammates can onboard quickly and run quality checks reliably.

Acceptance criteria

• Critical E2E flows pass for auth, map, analysis, and premium gating
• Bug bash is run and high-priority defects are resolved or triaged
• Contributor guide is updated with setup, scripts, and troubleshooting
• Release checklist is completed and signed off by frontend owner

Blocked by

VS-09 Export Vertical Slice (CSV/PDF Premium Gate)
VS-12 Summer Big Refactor (Architecture and Maintainability)