feat(proxy): add proxy pool and per-connection binding + strictProxy support

- Centralize proxy management with reusable proxy pools
- Per-connection proxy binding with legacy fallback
- Add strictProxy option: fail hard instead of silently falling back to direct
- Resolve alicode-intl conflict: keep alicode-intl support + proxy support

Made-with: Cursor

src/models/index.js

@@ -10,7 +10,18 @@ export {
   createProviderNode,
   updateProviderNode,
   deleteProviderNode,
+  getProxyPools,
+  getProxyPoolById,
+  createProxyPool,
+  updateProxyPool,
+  deleteProxyPool,
   deleteProviderConnectionsByProvider,
+  getCombos,
+  getComboById,
+  getComboByName,
+  createCombo,
+  updateCombo,
+  deleteCombo,
   getModelAliases,
   setModelAlias,
   deleteModelAlias,