📜 Archivist: Update mobile controls and squeak docs

[ScottMorris]

💡 What: Documented mobile controls alongside keyboard controls and added that squeaking shatters falling projectiles.
🎯 Why: To ensure documentation parity for mobile users and keep mechanics documentation truthful to the game's actual behaviour.
🔎 Where to read: rats-the-video-game/docs/mechanics.md

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PR created automatically by Jules for task 9216681113784270070 started by @ScottMorris

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[github-actions]

🐀 The Rats Have Deployed an Alpha!

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Squeak squeak!