Refactoring of the interaction system and preliminary integration of save/load functionality across the game. (#44)

### Interactables Architecture Refactor
- Converted composition to inheritance, moved from component-based to class-based interactables. No more requirement for chain of "Interactable -> Item" etc.
- Created `InteractableBase` abstract base class with common functionality that replaces the old component
- Specialized child classes: `Pickup`, `ItemSlot`, `LevelSwitch`, `MinigameSwitch`, `CombinationItem`, `OneClickInteraction` are now children classes
- Light updates to the interactable inspector, moved some things arround, added collapsible inspector sections in the  UI for better editor experience

### State Machine Integration
- Custom `AppleMachine` inheritong from Pixelplacement's StateMachine which implements our own interface for saving, easy place for future improvements
- Replaced all previous StateMachines by `AppleMachine`
- Custom `AppleState`  extends from default `State`. Added serialization, split state logic into "EnterState", "RestoreState", "ExitState" allowing for separate logic when triggering in-game vs loading game
- Restores directly to target state without triggering transitional logic
- Migration tool converts existing instances

### Prefab Organization
- Saved changes from scenes into prefabs
- Cleaned up duplicated components, confusing prefabs hierarchies
- Created prefab variants where possible
- Consolidated Environment prefabs and moved them out of Placeholders subfolder into main Environment folder
- Organized item prefabs from PrefabsPLACEHOLDER into proper Items folder
- Updated prefab references - All scene references updated to new locations
- Removed placeholder files from Characters, Levels, UI, and Minigames folders

### Scene Updates
- Quarry scene with major updates
- Saved multiple working versions (Quarry, Quarry_Fixed, Quarry_OLD)
- Added proper lighting data
- Updated all interactable components to new architecture

### Minor editor tools
- New tool for testing cards from an editor window (no in-scene object required)
- Updated Interactable Inspector
- New debug option to opt in-and-out of the save/load system
- Tooling for easier migration

Co-authored-by: Michal Pikulski <michal.a.pikulski@gmail.com>
Reviewed-on: #44

Packages/packages-lock.json

@@ -1,5 +1,14 @@
 {
   "dependencies": {
+    "com.coplaydev.unity-mcp": {
+      "version": "https://github.com/CoplayDev/unity-mcp.git?path=/MCPForUnity",
+      "depth": 0,
+      "source": "git",
+      "dependencies": {
+        "com.unity.nuget.newtonsoft-json": "3.0.2"
+      },
+      "hash": "e4904ad0d7ef37d68c30e447d6174e0203681489"
+    },
     "com.moolt.packages.net": {
       "version": "git+https://github.com/Moolt/UnityAudioSourceEvents?path=Packages/AudioSourceEvents",
       "depth": 0,
@@ -258,6 +267,13 @@
       "dependencies": {},
       "url": "https://packages.unity.com"
     },
+    "com.unity.nuget.newtonsoft-json": {
+      "version": "3.2.1",
+      "depth": 1,
+      "source": "registry",
+      "dependencies": {},
+      "url": "https://packages.unity.com"
+    },
     "com.unity.profiling.core": {
       "version": "1.0.2",
       "depth": 1,