fix: address review feedback on LocalSwapWidget and CheatsView

- LocalSwapWidget: move useWallet() to top-level <script setup> (was
  incorrectly called inside async buyKrk() event handler)
- LocalSwapWidget + CheatsView: fix misleading toast — all transactions
  are fully confirmed at that point, so say 'Swap complete' not 'Swap
  submitted'
- LocalSwapWidget: add $KRK sigil to warning/hint text for consistency
  with GetKrkView
- LocalSwapWidget: add comment on amountOutMinimum: 0n explaining it is
  intentional for a no-MEV local anvil environment
- CheatsView: apply same useWallet() fix (pre-existing anti-pattern)
- docs/ENVIRONMENT.md: document VITE_ENABLE_LOCAL_SWAP and related
  VITE_ variables in a new webapp env-var table

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

web-app/src/components/LocalSwapWidget.vue

@@ -1,7 +1,7 @@
 <template>
   <div class="local-swap-widget">
     <template v-if="!canSwap">
-      <p class="swap-warning">Connect your wallet to swap ETH for KRK on the local Uniswap pool.</p>
+      <p class="swap-warning">Connect your wallet to swap ETH for $KRK on the local Uniswap pool.</p>
     </template>
     <template v-else>
       <div class="swap-field">
@@ -11,7 +11,7 @@
       <button class="swap-button" :disabled="swapping" @click="buyKrk">
         {{ swapping ? 'Submitting…' : 'Buy KRK' }}
       </button>
-      <p class="swap-hint">Wraps ETH → WETH, approves the swap router, then trades into KRK.</p>
+      <p class="swap-hint">Wraps ETH → WETH, approves the swap router, then trades into $KRK.</p>
     </template>
   </div>
 </template>
@@ -28,6 +28,7 @@ import { useWallet } from '@/composables/useWallet';
 
 const toast = useToast();
 const { address, chainId } = useAccount();
+const { loadBalance } = useWallet();
 
 const swapAmount = ref('0.1');
 const swapping = ref(false);
@@ -240,17 +241,16 @@ async function buyKrk() {
           fee: 10_000,
           recipient: caller,
           amountIn: amount,
-          amountOutMinimum: 0n,
+          amountOutMinimum: 0n, // no slippage protection — acceptable on no-MEV local anvil
           sqrtPriceLimitX96: 0n,
         },
       ],
       chainId: currentChainId,
     });
 
-    const { loadBalance } = useWallet();
     await loadBalance();
 
-    toast.success('Swap submitted. Watch your wallet for KRK.');
+    toast.success('Swap complete. $KRK has been added to your wallet.');
   } catch (error: unknown) {
     toast.error(getErrorMessage(error, 'Swap failed'));
   } finally {