18: Level class created; first level with seed 42, subsequent random

[semere-meb]

Summary

Prepares Levels with generator and a fixed seed (42 for the first one, random for the subsequent)

Fixes #18

Changes

• New Level class to represent a level
• Properly ignored type issues for the mazegenerator package

Testing

• make lint passes locally
• make test passes locally (check N/A below if no tests exist yet for this area)
• Manually tested the behavior described above
• N/A — no automated tests apply to this change yet

Checklist

• PR title follows <TICKET-ID>: short description
• Linked to the correct issue (Fixes #... above)
• No unrelated changes bundled into this diff
• Updated docs/design/ if this changes config shape, architecture, or a game-design decision
• Updated README if this changes user-facing behavior (config keys, controls, etc.)