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/schema.prisma

@@ -46,6 +46,7 @@ model User {
   updatedAt           DateTime         @updatedAt @map("updated_at")
   tenant_members      tenant_members[]
   user_modules        user_modules[]
+  iitUserMappings     IitUserMapping[]
   departments         departments?     @relation(fields: [department_id], references: [id])
   tenants             tenants          @relation(fields: [tenant_id], references: [id])
 
@@ -950,17 +951,21 @@ model IitProject {
   lastSyncAt      DateTime?          @map("last_sync_at")
   cronEnabled     Boolean            @default(false) @map("cron_enabled")
   cronExpression  String?            @map("cron_expression")
+  isDemo          Boolean            @default(false) @map("is_demo")
   status          String             @default("active")
   createdAt       DateTime           @default(now()) @map("created_at")
   updatedAt       DateTime           @updatedAt @map("updated_at")
   deletedAt       DateTime?          @map("deleted_at")
+  tenantId        String?            @map("tenant_id")
   auditLogs       IitAuditLog[]
   pendingActions  IitPendingAction[]
   taskRuns        IitTaskRun[]
   userMappings    IitUserMapping[]
+  tenant          tenants?           @relation(fields: [tenantId], references: [id])
 
   @@index([status, deletedAt])
   @@index([knowledgeBaseId], map: "idx_iit_project_kb")
+  @@index([tenantId])
   @@map("projects")
   @@schema("iit_schema")
 }
@@ -1022,6 +1027,7 @@ model IitUserMapping {
   id                String     @id @default(uuid())
   projectId         String     @map("project_id")
   systemUserId      String     @map("system_user_id")
+  userId            String?    @map("user_id")
   redcapUsername    String     @map("redcap_username")
   wecomUserId       String?    @map("wecom_user_id")
   miniProgramOpenId String?    @unique @map("mini_program_open_id")
@@ -1030,11 +1036,13 @@ model IitUserMapping {
   createdAt         DateTime   @default(now()) @map("created_at")
   updatedAt         DateTime   @updatedAt @map("updated_at")
   project           IitProject @relation(fields: [projectId], references: [id])
+  user              User?      @relation(fields: [userId], references: [id])
 
   @@unique([projectId, systemUserId])
   @@unique([projectId, redcapUsername])
   @@index([wecomUserId])
   @@index([miniProgramOpenId])
+  @@index([userId])
   @@map("user_mappings")
   @@schema("iit_schema")
 }
@@ -1763,6 +1771,7 @@ model tenants {
   tenant_quotas            tenant_quotas[]
   users                    User[]
   user_modules             user_modules[]
+  iitProjects              IitProject[]
 
   @@index([code], map: "idx_tenants_code")
   @@index([status], map: "idx_tenants_status")
@@ -1819,6 +1828,7 @@ enum UserRole {
   HOSPITAL_ADMIN
   PHARMA_ADMIN
   DEPARTMENT_ADMIN
+  IIT_OPERATOR
   USER
 
   @@schema("platform_schema")