feat: complete Phase 1 infrastructure

- erp-core: error types, shared types, event bus, ErpModule trait
- erp-server: config loading, database/Redis connections, migrations
- erp-server/migration: tenants table with SeaORM
- apps/web: Vite + React 18 + TypeScript + Ant Design 5 + TailwindCSS
- Web frontend: main layout with sidebar, header, routing
- Docker: PostgreSQL 16 + Redis 7 development environment
- All workspace crates compile successfully (cargo check passes)

crates/erp-server/migration/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "erp-server-migration"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+sea-orm-migration.workspace = true
+tokio.workspace = true