reset interrupted runs before retry in the dev launcher

proxy timeouts can kill a build mid-flight, leaving orphaned containers on
the channel ports, dangling build cache, and half-written clones. clean
those on every start, scoped to the channel and keeping the DB volume, so a
re-run starts from a clean slate.

scripts/Start-ShopDBDev.ps1

@@ -48,6 +48,40 @@ param(
 
 $ErrorActionPreference = 'Stop'
 
+# Reset leftovers from an interrupted or timed-out prior run so the retry starts
+# clean. Proxy bottlenecks can kill a build mid-flight, leaving orphaned
+# containers holding the channel ports, dangling build cache from the partial
+# build, and sometimes a half-written clone. This is scoped to the channel and
+# is non-destructive to data: the compose down keeps named volumes (the DB), and
+# only dangling build cache is pruned - never tagged images or volumes.
+function Clear-InterruptedRun {
+	param(
+		[Parameter(Mandatory)][string]$Project,
+		[Parameter(Mandatory)][string]$Target
+	)
+
+	if (Get-Command docker -ErrorAction SilentlyContinue) {
+		# Only try compose down when the engine is actually responding, otherwise
+		# skip quietly - a fresh box may not have Docker started yet.
+		docker info *> $null
+		if ($LASTEXITCODE -eq 0) {
+			Write-Host "==> Cleaning up any interrupted '$Project' stack" -ForegroundColor Cyan
+			# --remove-orphans clears containers left by a killed build; volumes are
+			# intentionally kept so the DB survives a retry.
+			docker compose -p $Project down --remove-orphans *> $null
+			# Reclaim only dangling build cache from failed/partial builds.
+			docker builder prune -f *> $null
+		}
+	}
+
+	# A directory that exists but has no valid .git is a broken/partial clone;
+	# remove it so the clone below can start fresh instead of failing.
+	if ((Test-Path $Target) -and -not (Test-Path (Join-Path $Target '.git'))) {
+		Write-Host "==> Removing incomplete clone at $Target" -ForegroundColor Cyan
+		Remove-Item -Path $Target -Recurse -Force
+	}
+}
+
 # Plain https URL. No token in the URL: Git Credential Manager injects the
 # stored GitHub credential for github.com, so clone/fetch authenticate against
 # the private repo without anything sensitive touching this script or disk.
@@ -63,6 +97,9 @@ if (-not (Get-Command git -ErrorAction SilentlyContinue)) {
 	throw 'git is required. Install Git for Windows (winget install Git.Git) and re-run.'
 }
 
+$project = if ($Channel -eq 'edge') { 'shopdb-edge' } else { 'shopdb-stable' }
+Clear-InterruptedRun -Project $project -Target $target
+
 if (Test-Path (Join-Path $target '.git')) {
 	Write-Host "==> Updating existing clone" -ForegroundColor Cyan
 	git -C $target fetch origin $branch