fix: replace silent error swallowing with console.warn and user-facing error messages

All empty catch blocks across 8 Vue pages now log warnings. User-initiated
actions (fight, matchmake) also surface errors in the UI via fightError/loadError refs.

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

frontend/src/pages/BotProfilePage.vue

@@ -77,6 +77,8 @@ const waitingFighters = ref<QueueEntry[]>([])
 let pollHandle: ReturnType<typeof setInterval> | null = null
 
 const isOwner = ref(false)
+const loadError = ref('')
+const fightError = ref('')
 const showCustomize = ref(false)
 const isSaving = ref(false)
 const custError = ref('')
@@ -207,7 +209,11 @@ onMounted(async () => {
   try {
     const res = await fetch(`/api/bots/${encodeURIComponent(botName)}/stats`)
     if (res.ok) stats.value = await res.json()
-  } catch { /* */ }
+    else loadError.value = `Failed to load bot (${res.status})`
+  } catch (err) {
+    loadError.value = 'Network error loading bot profile'
+    console.warn('[BotProfile] load failed:', err)
+  }
   isLoading.value = false
 
   // Check ownership
@@ -229,32 +235,46 @@ async function pollQueue() {
       const data = await res.json()
       waitingFighters.value = data.queue || []
     }
-  } catch { /* */ }
+  } catch (err) {
+    console.warn('[BotProfile] queue poll failed:', err)
+  }
 }
 
 async function instantFight() {
   if (!stats.value || isJoining.value) return
   isJoining.value = true
+  fightError.value = ''
   try {
     const res = await fetch(`/api/queue/join/${stats.value.id}`, { method: 'POST' })
     if (res.ok) {
       const data = await res.json()
       router.push(`/arena/${data.fightId}`)
+    } else {
+      fightError.value = `Matchmaking failed (${res.status})`
     }
-  } catch { /* */ }
+  } catch (err) {
+    fightError.value = 'Network error starting fight'
+    console.warn('[BotProfile] instant fight failed:', err)
+  }
   isJoining.value = false
 }
 
 async function fightSpecific(opponentBotId: string) {
   if (!stats.value || isJoining.value) return
   isJoining.value = true
+  fightError.value = ''
   try {
     const res = await fetch(`/api/fights/matchmake/${stats.value.id}`, { method: 'POST' })
     if (res.ok) {
       const data = await res.json()
       router.push(`/arena/${data.fightId}`)
+    } else {
+      fightError.value = `Matchmaking failed (${res.status})`
     }
-  } catch { /* */ }
+  } catch (err) {
+    fightError.value = 'Network error starting fight'
+    console.warn('[BotProfile] fight specific failed:', err)
+  }
   isJoining.value = false
 }
 
@@ -275,7 +295,7 @@ const tierClass = (t: number) => `tier-${t}`
       </div>
 
       <div v-else-if="!stats" class="flex-1 flex items-center justify-center">
-        <p class="font-display text-text-muted">Bot not found.</p>
+        <p class="font-display text-text-muted">{{ loadError || 'Bot not found.' }}</p>
       </div>
 
       <template v-else>
@@ -426,6 +446,8 @@ const tierClass = (t: number) => `tier-${t}`
               </button>
             </div>
 
+            <p v-if="fightError" class="font-mono text-[10px] text-neon-pink mt-2">{{ fightError }}</p>
+
             <!-- Choose your fight panel -->
             <div v-if="showChoose" class="mt-3 border border-border bg-surface-raised/50 p-3">
               <p class="font-display text-[10px] font-bold text-text-muted tracking-[0.15em] mb-2">