Fix macOS controls, world creation, settings, and F11

[devin-ai-integration]

Summary

• Fix desktop macOS input selection after OSXCross by defining MINECRAFT_MACOS and using keyboard/mouse input instead of the iOS/Xperia controller path.
• Add F11 fullscreen toggling and document it in the README controls table.
• Fix macOS create-world dialog result ordering, keep world names editable, and add a Creative/Survival selector.
• Replace the placeholder macOS options alert with a working settings dialog for username, sensitivity, invert mouse, left-handed mode, and graphics, persisted to options.txt.
• Add an in-game Game tab button to switch the current level between Creative and Survival and save the level mode.
• Match the release flow used by v0.6.1-mavericks-r4: CI now packages MinecraftPE-mavericks-x86_64.zip / .tar.gz, uploads them as artifacts, and publishes them automatically on v* tags with SHA-256 release notes.

Review & Testing Checklist for Human

• Build on a macOS runner or OSXCross toolchain and confirm the app launches.
• Create a new world with a custom name/seed in both Creative and Survival and verify the saved world name/mode are correct.
• Verify keyboard/mouse controls in-world: WASD, mouse look, Space, Shift, inventory/menu keys.
• Open Options from the main menu and confirm username/sensitivity/toggles persist after closing/reopening.
• Press F11 in the macOS window and confirm fullscreen toggles cleanly.
• After merge, tag the next release (v0.6.1-mavericks-r5 or similar) and confirm the GitHub release has the two downloadable app archives and checksums.

Notes

Local checks:

• git diff --check passed.
• make -C handheld/project/osxproj print-sources passed.
• Full local macOS build could not run in this Linux VM because clang++ / macOS SDK flags are unavailable; GitHub macOS CI should perform the real build.

Link to Devin session: https://app.devin.ai/sessions/55f1522f4ca94ccc9b7080556da6dcee
Requested by: @j92580498-max

[devin-ai-integration]

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