fix(activity): close Phase 14 KEEP-VERIFY/EXTEND — 11 backend + 3 frontend-contract + 2 test-fidelity defects

Phase 14 (multi-type public-welfare activities) verification closure.

Backend (D1-D11):
- D1 CRITICAL: ActivityMapper.countRemainingCapacity had no @Select and no XML
  -> activity detail / register / approve all threw Invalid bound statement.
  Removed the shell; unified on ActivityRegistrationMapper.
- D2 CRITICAL: register & approve were read-then-write -> oversold under
  concurrency. Replaced with single atomic SQL (insertIfCapacityAvailable /
  approveIfCapacityAvailable, affectedRows==0 => full).
- D3 HIGH: activityType / orgRole never validated against production
  chk_activity_type / chk_org_role -> 500 only on PostgreSQL.
- D4 HIGH: ActivityListItemDTO had no activityType -> miniapp category tabs
  always empty (Gate failure).
- D5: male/female counts were fabricated as approvedCount/2; now real
  aggregation over user_profiles.gender.
- D6: minAge/maxAge was a TODO no-op; added assertAgeInRange.
- D7: registration_policy write-only; per-type eligibility now enforced
  (identity / local eligibility / gender quota).
- D8: POST /operator/activities dropped type, multi-org and capacity groups
  and set organizer_org_id to the operator user id; now delegates to
  createActivityFromAdmin (single implementation).
- D9: three operator write endpoints were mounted on the user-side
  ActivityController (dual implementation, zero callers) -> moved.
- D10: NPE on soft-deleted activity in getMyActivities; NPE/500 on missing
  admin form fields (Instant.parse(null)); tolerant time parsing added.
- D11: DTO lacked registeredCount / status / coverFileId / description
  -> card always showed 0 registered, "view detail", no cover, no summary.

Frontend contract (F1-F3):
- F1: miniapp category code "classroom" is not in the production whitelist
  (should be relationship_education); three types had no tab at all.
- F2: ui-activity-card read 7 fields that do not exist on the backend;
  now reads only real DTO fields, plus per-type badge and eligibility hint.
- F3: admin-web had no activity management page at all; added
  ActivityManagementView.vue (type-driven dynamic form, multi-org,
  capacity groups, publish/cancel) + /activities route and nav entry.

Test fidelity (T1-T2):
- T1: deleted two assertTrue(true) placeholder tests (testNoOverbooking,
  testNoDuplicateRegistration) that covered the exact broken invariants.
- T2: test schema lacked V023 columns/constraints and three tables; the
  activity tables were only in the OPTIONAL set (zero coverage) -> schema
  completed and moved to REQUIRED_IN_TEST_SCHEMA.

Tests: ActivityPhase14Test (23 cases), ActivityConstraintGuardTest (9 cases,
parses real db/migration/V*.sql plus miniapp source). Two negative-verification
rounds proved both guard families actually turn red.

Regression: 450 tests / 0 failures / 0 errors / 3 skipped / BUILD SUCCESS
(baseline 420). admin-web vue-tsc 0 error, vite build OK.

miniapp/pages/activity/activity.ts

@@ -52,12 +52,26 @@ Page({
     hasMore: true,
     firstLoaded: false,
     activeCategory: 'all',
+    /**
+     * 分类 Tabs。
+     *
+     * <p><b>Phase 14 修复</b>：code 必须**逐字等于**后端 {@code activities.activity_type}
+     * 的取值（生产约束 {@code chk_activity_type} 白名单）。此前这里写的是
+     * {@code classroom}，而生产白名单里根本没有该值（婚恋课堂是
+     * {@code relationship_education}）—— 点「婚恋课堂」Tab 恒为空白页。
+     *
+     * <p>守卫 {@code ActivityConstraintGuardTest#miniappCategoryCodesWithinProductionWhitelist}
+     * 会解析真实 DDL 校验本数组，改错即刻变红。
+     */
     categories: [
       { code: 'all', label: '全部' },
       { code: 'matchmaking', label: '公益联谊' },
-      { code: 'classroom', label: '婚恋课堂' },
+      { code: 'interest_social', label: '兴趣社交' },
+      { code: 'relationship_education', label: '婚恋课堂' },
+      { code: 'premarital_guidance', label: '婚前辅导' },
+      { code: 'marriage_custom_culture', label: '婚俗文化' },
       { code: 'anti_fraud', label: '反诈宣传' },
-    ],
+    ] as ActivityCategory[],
     /** @type {{title:string, description:string, illustration:string, actions:Array}} */
     emptyConfig: {
       title: '暂无进行中的活动',