Android TV preview (debugging build, PR #93)

Debug-keystore-signed release builds (same signing/minification as the app's normal release build type - see release.yml's comments) built from the feat/android-tv branch, for sideload-testing PR #93 before it merges. Not a real version release - versionName/versionCode are unchanged from v0.10.6.

• camusic-0.10.6-tv-preview-tv.apk - the new Android TV build. Install on a Google TV/Android TV device or emulator; launches via the LEANBACK_LAUNCHER row.
• camusic-0.10.6-tv-preview-mobile.apk - the phone build off the same branch/commit, included for side-by-side comparison. Behaviorally identical to v0.10.6.

See PR #93 for details: #93