feat(ai): Copilot 基因化 Phase 0 Task 1-4 — 迁移 + Entity + 规则引擎

- 4 表迁移: copilot_rules, copilot_insights, copilot_risk_snapshots, copilot_chat_logs
- 4 个 SeaORM Entity 对应新表
- JSONLogic 规则引擎 (evaluate + evaluate_rules) + 5 个单元测试

crates/erp-ai/src/entity/mod.rs

@@ -8,3 +8,7 @@ pub mod ai_risk_threshold;
 pub mod ai_suggestion;
 pub mod ai_tenant_config;
 pub mod ai_usage;
+pub mod copilot_chat_logs;
+pub mod copilot_insights;
+pub mod copilot_risk_snapshots;
+pub mod copilot_rules;