Frontend routes — Host workspace and contest overview

[Circuit-Overtime]

Parent: #6

Build the host-level workspace for organizations running one or more contests.

Routes

• /host — workspace overview
• /host/contests — contest list and filters
• /host/contests/new — contest creation wizard
• /host/contests/[contestId] — contest command center
• /host/settings — host organization settings

Requirements

• Responsive host navigation and contest switcher
• Contest health, timeline, participation, repository, and activity summaries
• Empty, loading, error, permission-denied, and populated states
• Typed mock data until backend contracts are planned

Acceptance criteria

• All routes are connected through the host shell
• Invalid or unavailable contest IDs have a safe state
• Keyboard navigation and mobile layouts work
• No backend implementation is included