feat(iit): QC deep fix + V3.1 architecture plan + project member management

QC System Deep Fix:
- HardRuleEngine: add null tolerance + field availability pre-check (skipped status)
- SkillRunner: baseline data merge for follow-up events + field availability check
- QcReportService: record-level pass rate calculation + accurate LLM XML report
- iitBatchController: legacy log cleanup (eventId=null) + upsert RecordSummary
- seed-iit-qc-rules: null/empty string tolerance + applicableEvents config

V3.1 Architecture Design (docs only, no code changes):
- QC engine V3.1 plan: 5-level data structure (CDISC ODM) + D1-D7 dimensions
- Three-batch implementation strategy (A: foundation, B: bubbling, C: new engines)
- Architecture team review: 4 whitepapers reviewed + feedback doc + 4 critical suggestions
- CRA Agent strategy roadmap + CRA 4-tool explanation doc for clinical experts

Project Member Management:
- Cross-tenant member search and assignment (remove tenant restriction)
- IIT project detail page enhancement with tabbed layout (KB + members)
- IitProjectContext for business-side project selection
- System-KB route access control adjustment for project operators

Frontend:
- AdminLayout sidebar menu restructure
- IitLayout with project context provider
- IitMemberManagePage new component
- Business-side pages adapt to project context

Prisma:
- 2 new migrations (user-project RBAC + is_demo flag)
- Schema updates for project member management

Made-with: Cursor

backend/prisma/migrations/20260228_add_iit_phase2_user_project_rbac/migration.sql

@@ -0,0 +1,21 @@
+-- Phase 2: User-Project Association + RBAC
+-- 1. IitUserMapping: add userId (nullable FK to platform_schema.users)
+-- 2. IitProject: add tenantId (nullable FK to platform_schema.tenants, for Phase 3)
+-- 3. UserRole enum: add IIT_OPERATOR role
+
+-- 1. Add user_id to user_mappings (nullable, gradual migration)
+ALTER TABLE "iit_schema"."user_mappings" ADD COLUMN IF NOT EXISTS "user_id" VARCHAR(255);
+ALTER TABLE "iit_schema"."user_mappings" ADD CONSTRAINT "user_mappings_user_id_fkey"
+  FOREIGN KEY ("user_id") REFERENCES "platform_schema"."users"("id")
+  ON DELETE SET NULL ON UPDATE CASCADE;
+CREATE INDEX IF NOT EXISTS "idx_iit_user_mappings_user_id" ON "iit_schema"."user_mappings"("user_id");
+
+-- 2. Add tenant_id to projects (nullable, Phase 3 will make it required)
+ALTER TABLE "iit_schema"."projects" ADD COLUMN IF NOT EXISTS "tenant_id" VARCHAR(255);
+ALTER TABLE "iit_schema"."projects" ADD CONSTRAINT "projects_tenant_id_fkey"
+  FOREIGN KEY ("tenant_id") REFERENCES "platform_schema"."tenants"("id")
+  ON DELETE SET NULL ON UPDATE CASCADE;
+CREATE INDEX IF NOT EXISTS "idx_iit_projects_tenant_id" ON "iit_schema"."projects"("tenant_id");
+
+-- 3. Add IIT_OPERATOR to UserRole enum
+ALTER TYPE "platform_schema"."UserRole" ADD VALUE IF NOT EXISTS 'IIT_OPERATOR' BEFORE 'USER';

backend/prisma/migrations/20260228_add_iit_project_is_demo/migration.sql

@@ -0,0 +1,2 @@
+-- Add is_demo flag to IIT projects (体验项目标记)
+ALTER TABLE iit_schema.projects ADD COLUMN IF NOT EXISTS is_demo BOOLEAN NOT NULL DEFAULT false;