refactor: 大规模模块拆分与重组，新增 aether-admin crate

- 新建独立 aether-admin crate 承载 admin 相关共享契约与纯辅助函数
- 拆分 ai_pipeline 下 kiro/private_envelope/conversion/planner 等大文件为子模块目录
- 重组 admin handlers 各业务域（billing/oauth/provider/system/users 等）为目录结构，移除 shared.rs/builders.rs 等反模式
- 移除 ai_pipeline runtime adapters 旧实现（claude/openai/gemini/kiro/vertex/antigravity 等），改由 provider transport 统一承载
- 移除 control_facade/execution_facade/auth_snapshot_facade 等冗余 facade 层
- 拆分 query/billing 与 query/monitoring 模块、state/runtime/payments 与 security 模块
- 扩展架构测试覆盖 admin_billing/admin_model/admin_users 等新模块
- 删除 docs/architecture/refactor-execution-plan.md 已完成的执行计划文档

apps/aether-gateway/src/handlers/admin/provider/endpoints_admin/reads.rs

@@ -0,0 +1,115 @@
+use crate::handlers::admin::request::AdminAppState;
+use aether_data_contracts::repository::provider_catalog::{
+    StoredProviderCatalogEndpoint, StoredProviderCatalogProvider,
+};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use super::payloads::{build_admin_provider_endpoint_response, endpoint_key_counts_by_format};
+
+pub(crate) async fn build_admin_provider_endpoints_payload(
+    state: &AdminAppState<'_>,
+    provider_id: &str,
+    skip: usize,
+    limit: usize,
+) -> Option<serde_json::Value> {
+    if !state.has_provider_catalog_data_reader() {
+        return None;
+    }
+
+    let provider = state
+        .read_provider_catalog_providers_by_ids(&[provider_id.to_string()])
+        .await
+        .ok()
+        .and_then(|mut providers| providers.drain(..).next())?;
+    let mut endpoints = state
+        .list_provider_catalog_endpoints_by_provider_ids(std::slice::from_ref(&provider.id))
+        .await
+        .ok()
+        .unwrap_or_default();
+    endpoints.sort_by(|left, right| {
+        right
+            .created_at_unix_secs
+            .unwrap_or_default()
+            .cmp(&left.created_at_unix_secs.unwrap_or_default())
+            .then_with(|| left.id.cmp(&right.id))
+    });
+    let keys = state
+        .list_provider_catalog_keys_by_provider_ids(std::slice::from_ref(&provider.id))
+        .await
+        .ok()
+        .unwrap_or_default();
+    let (total_keys_by_format, active_keys_by_format) = endpoint_key_counts_by_format(&keys);
+    let now_unix_secs = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .ok()
+        .map(|duration| duration.as_secs())
+        .unwrap_or(0);
+
+    Some(serde_json::Value::Array(
+        endpoints
+            .into_iter()
+            .skip(skip)
+            .take(limit)
+            .map(|endpoint| {
+                build_admin_provider_endpoint_response(
+                    &endpoint,
+                    &provider.name,
+                    total_keys_by_format
+                        .get(endpoint.api_format.as_str())
+                        .copied()
+                        .unwrap_or(0),
+                    active_keys_by_format
+                        .get(endpoint.api_format.as_str())
+                        .copied()
+                        .unwrap_or(0),
+                    now_unix_secs,
+                )
+            })
+            .collect(),
+    ))
+}
+
+pub(crate) async fn build_admin_endpoint_payload(
+    state: &AdminAppState<'_>,
+    endpoint_id: &str,
+) -> Option<serde_json::Value> {
+    if !state.has_provider_catalog_data_reader() {
+        return None;
+    }
+
+    let endpoint = state
+        .read_provider_catalog_endpoints_by_ids(&[endpoint_id.to_string()])
+        .await
+        .ok()
+        .and_then(|mut endpoints| endpoints.drain(..).next())?;
+    let provider = state
+        .read_provider_catalog_providers_by_ids(std::slice::from_ref(&endpoint.provider_id))
+        .await
+        .ok()
+        .and_then(|mut providers| providers.drain(..).next())?;
+    let keys = state
+        .list_provider_catalog_keys_by_provider_ids(std::slice::from_ref(&endpoint.provider_id))
+        .await
+        .ok()
+        .unwrap_or_default();
+    let (total_keys_by_format, active_keys_by_format) = endpoint_key_counts_by_format(&keys);
+    let now_unix_secs = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .ok()
+        .map(|duration| duration.as_secs())
+        .unwrap_or(0);
+
+    Some(build_admin_provider_endpoint_response(
+        &endpoint,
+        &provider.name,
+        total_keys_by_format
+            .get(endpoint.api_format.as_str())
+            .copied()
+            .unwrap_or(0),
+        active_keys_by_format
+            .get(endpoint.api_format.as_str())
+            .copied()
+            .unwrap_or(0),
+        now_unix_secs,
+    ))
+}