feat(iit): Initialize IIT Manager Agent MVP - Day 1 complete

- Add iit_schema with 5 tables
- Create module structure and types (223 lines)
- WeChat integration verified (Access Token success)
- Update system docs to v2.4
- Add REDCap source folders to .gitignore
- Day 1/14 complete (11/11 tasks)

git-cleanup-redcap.ps1

@@ -0,0 +1,16 @@
+# Git cleanup script for REDCap source code folders
+# Remove from Git tracking but keep local files
+
+cd D:\MyCursor\AIclinicalresearch
+
+Write-Host "Removing REDCap source folders from Git tracking..." -ForegroundColor Yellow
+
+# Remove from Git cache (but keep local files)
+git rm -r --cached redcap15.8.0 2>$null
+git rm -r --cached redcap_external_module_framework_docs_main 2>$null
+git rm -r --cached redcap_external_module_framework_docs_main/guanfangexternal-module-framework-docs-main 2>$null
+
+Write-Host "Cleanup complete! Files removed from Git but preserved locally." -ForegroundColor Green
+Write-Host ""
+Write-Host "Next step: Run the commit command" -ForegroundColor Cyan
+