Consolidate eager JavaScript chunks

[ridecontrol]

What changed

• removes the manually forced TanStack Router chunk
• lets Rolldown use its automatic split strategy for the shared application graph
• retains lazy chunks for route maps, the BikeGPX browser, and Garmin FIT processing
• raises the intentional entry-chunk warning threshold to cover the consolidated 512 KB uncompressed application entry

Why

The manual TanStack group caused every initial visit to fetch separate TanStack Router and Rolldown runtime files even though neither request deferred work. Disabling code splitting entirely would instead force the much larger map and FIT dependencies into every initial load.

Impact

The initial application graph falls from five JavaScript requests to three with essentially unchanged compressed bytes. The standalone tanstack-router and rolldown-runtime assets are gone, while expensive optional features remain on demand.

Validation

• bun run ci
• Biome clean with warnings treated as errors
• Tailwind diagnostics passed
• 270 unit tests passed
• TypeScript check passed
• production build passed without warnings