Rework toolbox tile gestures: tap to pick/edit, long-press to clear (v0.5.2)

Single tap now acts immediately instead of just selecting: an empty tile
opens the device picker, a filled tile opens its settings editor (this was
the double-tap behaviour; the highlight-only single-tap and the double-tap
are gone). Long-press clears the tile — but now via a confirmation dialog
("Clear tile") rather than wiping instantly, since clearing discards the
device and its settings with no undo (matches the preset DELETE confirm).
Long-pressing an empty tile does nothing.

Removes the now-unused per-tile `selected` state/highlight and onDoubleTap.
Verified on-device: filled→editor, empty→picker, long-press→confirm(Cancel
keeps the tile).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/build.gradle.kts

@@ -22,8 +22,8 @@ android {
         // (android.media.midi) and AAudio low-latency audio we rely on.
         minSdk = 26
         targetSdk = 34
-        versionCode = 16
-        versionName = "0.5.1"
+        versionCode = 17
+        versionName = "0.5.2"
 
         // We provide our own instrumentation runner if/when tests are added.
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"