refactor: extract shared FightData interface to fight/types.ts

Move FightData, FightRound, FightBot, FightArenaInfo types from local
definitions in FightViewer.vue to shared fight/types.ts. Replace `any`
typing in HumanFightPage, FightPage, useFightPolling, and useFightCache
with proper typed interfaces. Fix null-safety guards exposed by typing.

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

frontend/src/composables/useFightCache.ts

@@ -1,3 +1,5 @@
+import type { FightData } from '../game/fight/types'
+
 const DB_NAME = 'botfights_cache'
 const STORE_NAME = 'fights'
 const MAX_CACHED = 5
@@ -17,7 +19,7 @@ function openDB(): Promise<IDBDatabase> {
 }
 
 /** Cache a fight replay for offline viewing */
-export async function cacheFight(fightData: { id: string; [key: string]: any }): Promise<void> {
+export async function cacheFight(fightData: FightData): Promise<void> {
   try {
     const db = await openDB()
     const tx = db.transaction(STORE_NAME, 'readwrite')
@@ -50,7 +52,7 @@ export async function cacheFight(fightData: { id: string; [key: string]: any }):
 }
 
 /** Get a cached fight by ID */
-export async function getCachedFight(id: string): Promise<any | null> {
+export async function getCachedFight(id: string): Promise<FightData | null> {
   try {
     const db = await openDB()
     return new Promise((resolve) => {

frontend/src/composables/useFightPolling.ts

@@ -1,4 +1,5 @@
 import { ref, type Ref } from 'vue'
+import type { FightData, FightBot, FightArenaInfo } from '../game/fight/types'
 
 export interface LiveLogItem {
   type: string
@@ -8,11 +9,12 @@ export interface LiveLogItem {
 }
 
 export interface LiveFightData {
-  botA: any
-  botB: any
+  botA: FightBot | null
+  botB: FightBot | null
   arena: string
-  arenaInfo?: { name: string }
-  [key: string]: any
+  arenaInfo?: FightArenaInfo | null
+  mode?: string
+  potSats?: number
 }
 
 interface SSEListenerEntry {
@@ -25,7 +27,7 @@ export function useFightPolling(fightId: Ref<string>) {
   const isLoading = ref(true)
   const liveRounds = ref(0)
   const fightError = ref('')
-  const fight = ref<any>(null)
+  const fight = ref<FightData | null>(null)
   const liveFightData = ref<LiveFightData | null>(null)
   const spectatorCount = ref(0)
   const currentChallengeInfo = ref<{ type: string; label: string } | null>(null)