Rename package to cy.hexor.furumi, add F-Droid compatibility

- Rename applicationId and all sources from com.example.furumi_android to cy.hexor.furumi
- Add WTFPL LICENSE
- Add fastlane metadata
- Add fdroiddata build metadata cy.hexor.furumi.yml
- Remove foojay-resolver plugin (blocked by F-Droid scanner)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fastlane/metadata/android/en-US/changelogs/1.txt

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+Initial release.

fastlane/metadata/android/en-US/full_description.txt

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+Furumi is an Android client for the Furumi self-hosted music streaming server.
+
+Connect to your own Furumi instance and enjoy your personal music library from anywhere.
+
+Features:
+* Browse your music library — artists, albums, and tracks
+* Full playback controls with background playback support
+* Queue management and listening history
+* Connect and control multiple remote devices
+* Jam sessions — listen together with others
+* Secure authentication with token-based sessions
+* Material You design with edge-to-edge UI
+
+Furumi requires a running Furumi server instance to connect to.

fastlane/metadata/android/en-US/short_description.txt

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+Android client for the Furumi self-hosted music streaming server