build: add ESLint to script/lint and containerize linting (closes #152)

src/shared/prices.js

@@ -21,7 +21,7 @@ async function refreshPrices() {
         const fetched = await getTopTokenPrices(25);
         Object.assign(prices, fetched);
         lastFetchedAt = now;
-    } catch (e) {
+    } catch {
         // prices stay stale on error
     }
 }