Improve UX with merged run view, method badges, grouped encounters, and mobile nav

Merges the run dashboard into the encounters page as a unified view at /runs/:runId,
adds encounter method grouping in the modal and badges on route rows, improves the
home page with recent runs, adds mobile hamburger nav, and polishes empty states.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/index.ts

@@ -1,3 +1,4 @@
+export { EncounterMethodBadge } from './EncounterMethodBadge'
 export { EncounterModal } from './EncounterModal'
 export { EndRunModal } from './EndRunModal'
 export { GameCard } from './GameCard'