Add visible badges on boss Pokemon that have mechanic-related conditions (Mega Evolution, Gigantamax, Dynamax, Terastallize). Create a ConditionBadge component following the EncounterMethodBadge pattern and integrate it into BossDefeatModal and BossTeamPreview.
## Checklist
- [x] Create ConditionBadge component in frontend/src/components/ConditionBadge.tsx
- [x] Add ConditionBadge to BossDefeatModal.tsx boss team preview
- [x] Add ConditionBadge to RunEncounters.tsx BossTeamPreview