chore(site): drop dead coupon code and stale product-spec facts

script.js: delete applyCoupon(). Its only caller was the coupon button deleted above,
so the function was unreachable dead code that still carried the removed 'Coupon FREE
TRIAL applied - 1 month free' promise in a publicly served file. It would also have
thrown on the two DOM ids that no longer exist.

PRODUCT.md: this file is served publicly and still advertised $19.40/mo, $36.25/mo,
$49.60/mo, the FREE TRIAL coupon, 'yearly billing saves roughly 8-10%', a 'Satisfied
or reimbursed' guarantee and 'redundant slots'. Corrected to the yearly list prices
the site publishes and to the decisions above.

script.js

@@ -295,20 +295,6 @@ var si = 0,
                         encodeURIComponent(loc) +
                         (utmQuery ? "&" + utmQuery : "");
                 });
-            function applyCoupon() {
-                var input = document.getElementById("orderCouponInput");
-                var status = document.getElementById("orderCouponStatus");
-                var code = input.value.trim();
-                if (code.toLowerCase() === "free trial") {
-                    status.textContent =
-                        "\u2713 Coupon FREE TRIAL applied - 1 month free";
-                    status.style.color = "#1a7f37";
-                } else {
-                    status.textContent = "Invalid coupon code";
-                    status.style.color = "#dc3545";
-                }
-                status.style.display = "block";
-            }
             /* ---- Blog Module ---- */
             var blogState = {
                 allPosts: [],