后端：资料距离、语音图片会员限制、免短信注册、AI 托管回复修复

- 单用户资料接口补上距离：此前只有推荐/附近列表会算距离，资料页和
  聊天头部因此无内容可显示。沿用同一套 haversine 与隐私开关。
- 语音/图片消息可限定会员发送，两个开关在管理端「运营配置」中修改
  （迁移 032）。校验放在 persistMessageContext，HTTP 与 WebSocket
  两条发送路径都覆盖；文本消息永不受限。
- 短信服务关闭时注册不再要求验证码：关掉之后没人能拿到验证码，继续
  要求就等于关闭注册通道。重置密码不做同样放宽，那里缺验证码等于
  凭手机号夺号。app/config 增加 smsVerification 供客户端决定表单形态。
- 修复 AI 托管账号之间不回复：原规则按「发送方是否托管账号」拦截，
  把真人操作测试号的正常对话也挡了。改为标记 worker 自己写入的回复，
  只对 AI 生成的消息跳过入队。
- ai.default_model_id 同时接受模型 ID 与名称，填名称时不再被 MySQL
  静默转成 0 而使配置失效。
- 聊天媒体留存管理与清理任务（迁移 033，两台线上均已应用）。

新增集成测试均针对真实 MySQL：会员限制、免短信注册、AI 入队规则、
默认模型解析、资料距离。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

im/backend/internal/app/membership.go

@@ -75,7 +75,12 @@ func (a *App) membershipStatus(w http.ResponseWriter, r *http.Request) {
 			likeRemaining = 0
 		}
 	}
-	entitlementView := map[string]any{"dailyActiveChatLimit": entitlements.DailyActiveChatLimit, "dailyLikeLimit": entitlements.DailyLikeLimit, "dailyLikeUsed": likeUsed, "dailyLikeRemaining": likeRemaining, "canViewVisitors": entitlements.CanViewVisitors, "canInvisibleVisit": entitlements.CanInvisibleVisit, "recommendationWeight": entitlements.RecommendationWeight}
+	// The chat page reads these two to explain the lock before a recording or an
+	// upload is made, instead of letting the send fail after the work is done.
+	_, voiceGated := a.messageMembershipGate(r.Context(), messageTypeVoice)
+	_, imageGated := a.messageMembershipGate(r.Context(), messageTypeImage)
+	member := a.hasActiveMembership(r.Context(), current(r).ID)
+	entitlementView := map[string]any{"dailyActiveChatLimit": entitlements.DailyActiveChatLimit, "dailyLikeLimit": entitlements.DailyLikeLimit, "dailyLikeUsed": likeUsed, "dailyLikeRemaining": likeRemaining, "canViewVisitors": entitlements.CanViewVisitors, "canInvisibleVisit": entitlements.CanInvisibleVisit, "recommendationWeight": entitlements.RecommendationWeight, "voiceMessageRequiresVip": voiceGated, "imageMessageRequiresVip": imageGated, "canSendVoiceMessage": member || !voiceGated, "canSendImageMessage": member || !imageGated}
 	var planName string
 	var level int
 	var expires time.Time
@@ -339,6 +344,9 @@ func (a *App) appConfig(w http.ResponseWriter, r *http.Request) {
 		"feed":       a.configBool(r.Context(), "app.features.feed", true),
 		"membership": a.configBool(r.Context(), "app.features.membership", true),
 		"im":         a.configBool(r.Context(), "app.features.im", true),
+		// The sign-up form hides its code field when this is off, instead of
+		// asking for something the server will never send.
+		"smsVerification": a.smsVerificationRequired(r.Context()),
 	}
 	reply(w, map[string]any{"configs": configs, "platform": platform, "features": features, "maintenance": map[string]any{"enabled": a.configBool(r.Context(), "app.maintenance.enabled", false), "message": a.configPlain(r.Context(), "app.maintenance.message", "系统维护中，请稍后再试")}, "legal": map[string]string{"userAgreementVersion": a.configPlain(r.Context(), "legal.user_agreement_version", "1.0"), "privacyPolicyVersion": a.configPlain(r.Context(), "legal.privacy_policy_version", "1.0"), "operatorName": a.configPlain(r.Context(), "legal.operator_name", ""), "contact": a.configPlain(r.Context(), "legal.contact", ""), "effectiveDate": a.configPlain(r.Context(), "legal.effective_date", ""), "userAgreementUrl": a.configPlain(r.Context(), "legal.user_agreement_url", ""), "privacyPolicyUrl": a.configPlain(r.Context(), "legal.privacy_policy_url", "")}, "minVersion": a.configPlain(r.Context(), "app.min_version."+platform, "1.0.0"), "latest": latest})
 }