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

Package-Workspace/Business-Apps/InvenTree/CloudronManifest.json

@@ -0,0 +1,23 @@
+{
+  "manifestVersion": 2,
+  "type": "app",
+  "id": "io.cloudron.inventree",
+  "title": "InvenTree",
+  "description": "Open-source inventory management system: parts and stock tracking, bills of materials, suppliers, purchase and build orders, with a plugin ecosystem and REST API. PostgreSQL storage, Redis-backed background workers. SSO via the Cloudron OIDC provider; a local admin account is seeded on first boot (generated password in /app/data/.admin_password).",
+  "author": "InvenTree contributors",
+  "website": "https://inventree.org/",
+  "contactEmail": "cloudron@tsys.dev",
+  "tagline": "Inventory management: parts, stock, BOMs and orders",
+  "version": "1.5.2",
+  "healthCheckPath": "/api/system/health/",
+  "httpPort": 8000,
+  "memoryLimit": 2048,
+  "addons": {
+    "localstorage": {},
+    "postgresql": {},
+    "redis": {}
+  },
+  "mediaLinks": [],
+  "changelog": "Initial Cloudron package for InvenTree 1.5.2 (official-image wrapper of inventree/inventree, digest pinned). start.sh maps the postgresql/redis addons onto INVENTREE_* env, persists secret key + generated admin password under /app/data, builds the django-allauth openid_connect provider JSON from the Cloudron OIDC env, drives `invoke update` (migrations + static) before serving, and backgrounds the RQ worker gated on the web port. Health endpoint /api/system/health/ per upstream convention.",
+  "icon": "file://logo.png"
+}