fix: remove unused catch variable in artifact verification (#1839)

## Summary
- remove the unused `error` binding from `scripts/verify-artifacts.js`
- preserve the existing size-limit failure handling

Fixes the pre-existing Biome autofix/lint failure identified in #1833.

## Validation
- `npx --yes @biomejs/biome@2.5.11 check scripts/verify-artifacts.js`
- `node --check scripts/verify-artifacts.js`
- `git diff --check`

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: yamcodes

scripts/verify-artifacts.js

@@ -73,7 +73,7 @@ console.log("\n📦 Running size-limit validation...");
 try {
 	execSync("pnpm --filter arkenv run size", { cwd: rootDir, stdio: "inherit" });
 	console.log("✅ Passed: size-limit validation");
-} catch (error) {
+} catch {
 	console.error("❌ Error: size-limit validation failed");
 	process.exit(1);
 }