chore: add project scaffolding, third-party assets and settings

- Terrain, Prefabs, Textures, Modelle (u. a. Lieferkarton-/Vibrations-
  Rohdaten in Assets/Data)
- Third-Party-Pakete: TextMesh Pro, Toby Fredson Foliage Engine, Sat
  Productions Street Lights, ProBuilder Data
- Neue Szene Boot.unity, Shop-Szenenordner
- Package-Manifest/Lock, ProjectSettings, Build-Profile, .slnx
- Doku: EDITOR_SETUP.md, INSTALL.md, TODO.md

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

ProjectSettings/Packages/com.unity.progrids/Settings.json

@@ -0,0 +1,5 @@
+{
+    "m_Dictionary": {
+        "m_DictionaryValues": []
+    }
+}