feat(plugin): Schema 缓存 — moka LRU Cache 消除 resolve_entity_info 重复查库

- 添加 moka 0.12 依赖到 erp-plugin 和 erp-server
- 重写 state.rs: 新增 EntityInfo (含 generated_fields) 和 moka Cache
- AppState 新增 plugin_entity_cache 字段
- data_service.rs: 旧 resolve_entity_info 保留兼容，新增 resolve_entity_info_cached

crates/erp-plugin/Cargo.toml

@@ -23,3 +23,4 @@ utoipa = { workspace = true }
 async-trait = { workspace = true }
 sha2 = { workspace = true }
 base64 = "0.22"
+moka = { version = "0.12", features = ["sync"] }