fix: Fix product page syntax errors

1. Remove duplicate/broken code in product tables section
2. Fix PostCSS config for Tailwind 4
3. Add @tailwindcss/postcss dependency
4. Remove --production flag from Dockerfile (sharp required)

All fixes enable successful Docker build with favicon working.

node_modules/extend/.eslintrc

@@ -0,0 +1,17 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"complexity": [2, 20],
+		"eqeqeq": [2, "allow-null"],
+		"func-name-matching": [1],
+		"max-depth": [1, 4],
+		"max-statements": [2, 26],
+		"no-extra-parens": [1],
+		"no-magic-numbers": [0],
+		"no-restricted-syntax": [2, "BreakStatement", "ContinueStatement", "DebuggerStatement", "LabeledStatement", "WithStatement"],
+		"sort-keys": [0],
+	}
+}