City redirect shortcut (/city-slug/ → latest event)

[mattstratton]

Context

PRD Appendix B — The Hugo site supports `/city/` as a redirect to the current year's event for that city (e.g., `/chicago/` → `/events/2026-chicago/`).

Requirements

• `//` redirects to the most recent (or current year's) event for that city
• If no current event, redirect to the most recent past event
• If city doesn't exist, return 404 (don't conflict with static pages)

Implementation Notes

• Need to be careful about URL routing order: static pages also use `//`
• Could check City model first, then fall back to StaticPage
• Or use a combined view that checks both

Acceptance Criteria

• `/chicago/` redirects to `/events/2026-chicago/` (or latest)
• `/amsterdam/` redirects to latest Amsterdam event
• Unknown slugs that aren't cities or static pages return 404
• No conflicts between city redirects and static page routes

References

• PRD Appendix B — URL Mapping (`/city/` pattern)