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

frontend-v2/src/modules/legacy/LegacySystemPage.tsx

@@ -51,7 +51,7 @@ const LegacySystemPage: React.FC<LegacySystemPageProps> = ({ targetUrl }) => {
       authDoneRef.current = true
       setStatus('ready')
     } catch (err: any) {
-      const msg = err?.response?.data?.message || err?.message || '旧系统认证失败'
+      const msg = err?.response?.data?.message || err?.message || '服务连接失败，请稍后重试'
       setErrorMsg(msg)
       setStatus('error')
       message.error(msg)
@@ -66,7 +66,7 @@ const LegacySystemPage: React.FC<LegacySystemPageProps> = ({ targetUrl }) => {
     return (
       <div style={{ display: 'flex', flexDirection: 'column', alignItems: 'center', justifyContent: 'center', height: '100%', gap: 16 }}>
         <Spin indicator={<LoadingOutlined style={{ fontSize: 36 }} spin />} />
-        <span style={{ color: '#666' }}>正在连接旧系统...</span>
+        <span style={{ color: '#666' }}>正在加载...</span>
       </div>
     )
   }
@@ -96,7 +96,7 @@ const LegacySystemPage: React.FC<LegacySystemPageProps> = ({ targetUrl }) => {
         border: 'none',
         display: 'block',
       }}
-      title="旧系统"
+      title="模块加载"
     />
   )
 }