Replace hand-edited JSON with a setup wizard

Melissa had to author entity.json by hand and know FTPS from SFTP to do
it - which is what broke the last two CAMBS runs. setup-entity.bat now
asks the questions and writes the file:

- protocol is a numbered menu, stored as an explicit "protocol" key that
  wins over the sftp:// host prefix and the older tls flag
- pasted schemes and paths are stripped off the host before saving
- it creates the practice folders, then logs in and checks every
  practice's remote folder exists, so a wrong path or protocol surfaces
  in seconds instead of in the next morning's run

Also drops insurance_file_type from the required path: with no setting
the engine sends every file in the date folder minus Windows clutter, so
"No .pdf files" can't happen on a folder full of TIFs. Connection
failures now print what to change rather than just WinSCP's wording.

run-all.ps1

@@ -3,15 +3,15 @@ $scriptRoot  = Split-Path -Parent $MyInvocation.MyCommand.Path
 $entitiesDir = Join-Path $scriptRoot "Entities"
 
 if (-not (Test-Path $entitiesDir)) {
-    Write-Host "ERROR: Entities\ folder not found." -ForegroundColor Red
-    exit 1
+    Write-Host "Nothing is set up yet - double-click setup-entity.bat first." -ForegroundColor Yellow
+    exit 0
 }
 
-$entities = Get-ChildItem -Path $entitiesDir -Directory |
-            Where-Object { Test-Path (Join-Path $_.FullName "entity.json") }
+$entities = @(Get-ChildItem -Path $entitiesDir -Directory |
+              Where-Object { $_.Name -ne "EXAMPLE" -and (Test-Path (Join-Path $_.FullName "entity.json")) })
 
 if ($entities.Count -eq 0) {
-    Write-Host "No entity folders with entity.json found under Entities\." -ForegroundColor Yellow
+    Write-Host "No entities are set up yet - double-click setup-entity.bat to add one." -ForegroundColor Yellow
     exit 0
 }