feat: initialize ERP base platform (extracted from HMS)

- Stripped 11 business crates (health, ai, dialysis, plugins)
- Cleaned AppState, AppConfig, main.rs from business coupling
- Reduced migrations from 169 to 53 (base-only)
- Removed health_provider trait from erp-core
- Removed business integration tests
- Removed gateway rate limiting middleware
- Base capabilities: auth, RBAC, JWT, config, workflow, message, plugin, audit, crypto, RLS, multi-tenant

Cargo check: OK
Cargo test: OK

crates/erp-plugin/src/error.rs

@@ -0,0 +1,55 @@
+use erp_core::error::AppError;
+
+/// 插件模块错误类型
+#[derive(Debug, thiserror::Error)]
+pub enum PluginError {
+    #[error("插件未找到: {0}")]
+    NotFound(String),
+
+    #[error("插件已存在: {0}")]
+    AlreadyExists(String),
+
+    #[error("无效的插件清单: {0}")]
+    InvalidManifest(String),
+
+    #[error("无效的插件状态: 期望 {expected}, 实际 {actual}")]
+    InvalidState { expected: String, actual: String },
+
+    #[error("插件执行错误: {0}")]
+    ExecutionError(String),
+
+    #[error("插件实例化错误: {0}")]
+    InstantiationError(String),
+
+    #[error("插件 Fuel 耗尽: {0}")]
+    FuelExhausted(String),
+
+    #[error("依赖未满足: {0}")]
+    DependencyNotSatisfied(String),
+
+    #[error("数据库错误: {0}")]
+    DatabaseError(String),
+
+    #[error("权限不足: {0}")]
+    PermissionDenied(String),
+
+    #[error("配置校验失败: {0}")]
+    ValidationError(String),
+}
+
+impl From<PluginError> for AppError {
+    fn from(err: PluginError) -> Self {
+        match &err {
+            PluginError::NotFound(_) => AppError::NotFound(err.to_string()),
+            PluginError::AlreadyExists(_) => AppError::Conflict(err.to_string()),
+            PluginError::InvalidManifest(_)
+            | PluginError::InvalidState { .. }
+            | PluginError::DependencyNotSatisfied(_)
+            | PluginError::ValidationError(_) => AppError::Validation(err.to_string()),
+            PluginError::PermissionDenied(_) => AppError::Forbidden(err.to_string()),
+            _ => AppError::Internal(err.to_string()),
+        }
+    }
+}
+
+pub type PluginResult<T> = Result<T, PluginError>;