fix: suppress compiler warnings in BacktestRunner (#316)

- Add `view` to _parseSqrtPriceFromFile and _resolveSqrtPrice
- Remove unused IUniswapV3Pool import

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

onchain/script/backtesting/BacktestRunner.s.sol

@@ -3,7 +3,6 @@ pragma solidity ^0.8.19;
 
 import { Script } from "forge-std/Script.sol";
 import { console2 } from "forge-std/console2.sol";
-import { IUniswapV3Pool } from "@uniswap-v3-core/interfaces/IUniswapV3Pool.sol";
 import { MockToken } from "./MockToken.sol";
 import { ShadowPool, ShadowPoolDeployer } from "./ShadowPoolDeployer.sol";
 
@@ -37,7 +36,7 @@ contract BacktestRunner is Script {
      *      fetch-events.ts serialises BigInt values as decimal strings, so we use
      *      parseJsonString then parseUint rather than parseJsonUint.
      */
-    function _parseSqrtPriceFromFile(string memory eventsFile) external returns (uint160) {
+    function _parseSqrtPriceFromFile(string memory eventsFile) external view returns (uint160) {
         string memory line = vm.readLine(eventsFile);
         string memory sqrtStr = vm.parseJsonString(line, ".sqrtPriceX96");
         return uint160(vm.parseUint(sqrtStr));
@@ -48,7 +47,7 @@ contract BacktestRunner is Script {
      * @dev Call this BEFORE vm.startBroadcast() — the `this.` external call must not
      *      be included in the broadcast.
      */
-    function _resolveSqrtPrice() internal returns (uint160) {
+    function _resolveSqrtPrice() internal view returns (uint160) {
         // 1. Explicit env override.
         try vm.envUint("INITIAL_SQRT_PRICE_X96") returns (uint256 val) {
             if (val != 0) return uint160(val);