feat(vip): restructure membership settings into structured groups

Replace the pipe-delimited VIP configuration with structured groups and
accordions, matching the reference theme (Zibll) 1:1.

Settings:
- 会员等级 keeps only the nav buttons and the two level switches, plus the
  "must enable level 1 first" guard. Level identity fields (display name,
  intro, benefits HTML, icon) and 会员商品 move into the 一级会员/二级会员
  tabs of 会员购买选项, so each level is configured in one place.
- Level tab titles bind to the configured display name via a new
  titleKey/titleFallback hook in AksFormRenderer.
- 会员商品 is a repeater with exactly the reference fields: 执行价/原价/
  促销标签/标签颜色/会员有效时间/时长单位. The tag colour uses the full
  b+jb palette and now reaches the product card instead of a hardcoded
  jb-yellow.
- 会员续费 gains the 自定义商品 type backed by per-level renew-product
  groups; the discount becomes a 0.1-9.9 slider with float sanitizing.
- 会员升级 becomes the reference three-block accordion (month-to-month
  day-rate, jump to permanent, permanent to permanent), each with its own
  price, strikethrough price, promo tag and tag colour.
- 积分兑换明细 is a repeater (points/level/duration/unit) where the
  duration accepts the literal Permanent.

Runtime:
- PaymentRuntime normalizes the structured groups into purchasable rows
  (money normalization, palette validation, zero-price and out-of-range
  rows dropped) and no longer emits any *_raw strings.
- The catalog builder carries tag_class through and routes renewals to the
  renew-product group under 自定义商品.
- The points-exchange order note carries time/unit so month durations use
  calendar math instead of a 30-day approximation.

Dead code removed: parse_level_products, parse_packages,
parse_upgrade_product_line and their pipe-splitting, plus nine zero-call
PaymentRuntime proxy methods in HomeCms. No dual-format or migration path
was added; SchemaProvider already falls back to defaults when a stored
group value is not an array, so existing pipe strings degrade safely.

Verified: php -l on every changed PHP file, 655 Node contract tests passing
(14 new ones in vip-settings-structured-contract.test.cjs exercising the
real schema build and runtime normalization via a PHP harness), and the
admin SPA builds.

assets/admin/src/components/form/AksField.vue

@@ -1053,6 +1053,8 @@ const repeaterDraft = ref({})
 function createRepeaterItem() {
   const newItem = { _id: `rpt_${Date.now()}_${++repeaterIdCounter}` }
   for (const field of (props.schema.fields || [])) {
+    // UI-only chrome rows (notice / alert) are presentation only.
+    if (field.ui_only) continue
     if (field.default !== undefined) {
       newItem[field.key] = field.default
     } else if (field.type === 'switch') {

assets/admin/src/components/form/AksFormRenderer.vue

@@ -64,9 +64,9 @@
                   <n-tabs type="line" animated>
                     <n-tab-pane
                       v-for="tab in field.tabs"
-                      :key="tab.title || tab.key"
-                      :name="tab.title || tab.key"
-                      :tab="tab.title || tab.key"
+                      :key="tab.key || tab.title"
+                      :name="tabName(tab)"
+                      :tab="tabName(tab)"
                     >
                       <template v-for="sub in (tab.fields || [])" :key="sub.key">
                         <AksField
@@ -231,6 +231,18 @@ function isFieldVisible(field) {
   return matchDependsOn(field.dependsOn)
 }
 
+/**
+ * Tab label. `titleKey` binds the label to a live form value (e.g. the VIP level
+ * display name) so renaming a level renames its tab; `titleFallback` is used
+ * while that value is still empty.
+ */
+function tabName(tab) {
+  if (!tab) return ''
+  const dynamic = tab.titleKey ? props.formData?.[tab.titleKey] : ''
+  const label = typeof dynamic === 'string' ? dynamic.trim() : ''
+  return label || tab.titleFallback || tab.title || tab.key || ''
+}
+
 /** Whole group can be hidden (e.g. optional advanced blocks). */
 function isGroupVisible(group) {
   return matchDependsOn(group.dependsOn)