Generalize USMT Dash and add a containerized demo mode

Remove all environment-specific data and make the dashboard adoptable
anywhere, then add a demo that runs the real PowerShell services.

- Strip cached device data, internal knowledge-base articles and
  screenshots, server/site names and the old project notes; replace the
  knowledge base with generic sample articles and diagrams
- Move every environment value into Config/usmt-dash.psd1
- Route all infrastructure access in the worker and Get-Software.ps1
  through a provider (Providers/SCCM.ps1), with a config-driven asset
  inventory view instead of a hard-coded custom class
- Add Providers/Demo.ps1: a deterministic simulated fleet whose
  migrations progress in real time, and Demo/New-DemoData.ps1 to seed it
- Server: -Demo makes the API read-only; add get-config and get-logs;
  serve static files only from web/, Documentation/ and an allowlist of
  Data/ files with a path-traversal guard; gzip large responses
- Mirror both services' console output to Data/Logs via a Write-Host
  proxy, and add a terminal panel to the dashboard that streams it
- Demo sandbox (web/demo/demo.js): visitor changes to tags, articles and
  images are kept in the visitor's browser and echoed in the terminals;
  nothing a visitor does reaches the server
- Vendor marked, highlight.js and html2pdf.js instead of loading CDNs
- Dockerfile and compose file for hosting the demo (Coolify-ready)

Documentation/WMI Namespace Fix.md

@@ -0,0 +1,31 @@
+[[Yellow:Remediation]] [[Red:Admin Required]]
+
+# WMI Namespace Fix
+
+Symptoms: Software Center is blank, the ConfigMgr client shows *Inactive*, or the backup task sequence fails with WMI errors (`0x80041003`, `0x8004100e`).
+
+## 1. Verify the repository
+Open an **elevated** PowerShell:
+```powershell
+winmgmt /verifyrepository
+```
+- `WMI repository is consistent`: skip to step 3.
+- `inconsistent`: continue.
+
+## 2. Salvage the repository
+```powershell
+winmgmt /salvagerepository
+```
+Run `/verifyrepository` again. If it's still inconsistent, as a **last resort**:
+```powershell
+winmgmt /resetrepository
+```
+
+## 3. Repair the ConfigMgr client
+```powershell
+& "$env:WinDir\CCM\ccmrepair.exe"
+```
+Wait 10-15 minutes, then confirm **Configuration Manager** in Control Panel lists its actions.
+
+## 4. Re-check in USMT Dash
+The client status in the device details should return to *Installed / Active* after the next hardware inventory cycle.