Added Test-Sandbox, Additional Ending & various Prototype Systems

This is a slightly wild update. Some quality of life things. Some design things. A new Sandbox to test upcoming features.

Feel free to check out the sandbox. It contains some sneak peaks into future mechanics of the game. 

--------------- 04.11.2025 ---------------
- Added CSS for dialogues in REINCARNATIONS
- Set up hag_hut location dummy
- Prepared "Prophecy" game loop concept
- Prepared "Harbinger of Doom" questline concept
- Set up Development Sandbox for feature tests
- Set up "ERROR 404" Ending.
- Set up "Harbinger of Doom" Sneak Peak in the Development Sandbox
- Set up basic image integration with Base64 image encoding
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