feat: add InvenTree Cloudron package (Business-Apps) [#658]

Official-image wrapper of inventree/inventree 1.5.2 (digest-pinned).
allauth OIDC provider JSON built from the platform env; invoke update
on boot; RQ worker behind the web-port gate; admin seeded with a
generated password. grind-stack: lowercase image names. 19th package.
Verified: health 200, SSO route 302s to issuer, migrations clean.

Detail: https://projects.knownelement.com/issues/658#note-5086

scripts/grind-stack.sh

@@ -41,7 +41,7 @@ manifest_field() { jq -r "$1" "$PKG/CloudronManifest.json"; }
 cmd_up() {
   PKG="${1:?usage: grind-stack.sh up <pkg-dir>}"
   [ -f "$PKG/CloudronManifest.json" ] || die "no CloudronManifest.json in $PKG"
-  APPNAME="$(basename "$PKG")"
+  APPNAME="$(basename "$PKG" | tr '[:upper:]' '[:lower:]')"
   PORT="$(manifest_field .httpPort)"
   MEM="$(manifest_field .memoryLimit)"
   ADDONS="$(jq -r '.addons | keys[]' "$PKG/CloudronManifest.json" | sort | tr '\n' ' ')"
@@ -121,7 +121,7 @@ cmd_down() {
 
 cmd_sweep() {
   PKG="${1:?usage: grind-stack.sh sweep <pkg-dir>}"
-  APPNAME="$(basename "$PKG")"
+  APPNAME="$(basename "$PKG" | tr '[:upper:]' '[:lower:]')"
   echo "== grind sweep: $APPNAME"
   stack_running && die "stack still up - run 'down' before sweep"
   docker image rm "grind-$APPNAME:test" >/dev/null 2>&1 || echo "  (test image already gone)"