Rename application identifier to space.rcmd.android.sizzle

Global rename of the app/package identifier from
com.reactorcoremeltdown.sizzletracker to space.rcmd.android.sizzle:

- build.gradle.kts: applicationId + namespace.
- Move the Kotlin source tree (main + test) and rewrite every package/import.
- native_audio.cpp: JNI symbol names (Java_space_rcmd_android_sizzle_...) so the
  Oboe callback still links against the relocated NativeAudioBridge.
- docs: package/file-map header.

The desktop-project GitHub URLs (github.com/reactorcoremeltdown/sizzletracker)
and the Reactorcoremeltdown copyright/SPDX author identity are intentionally left
unchanged. Note: the new applicationId installs as a separate package (existing
installs won't upgrade in place).

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

app/src/main/java/space/rcmd/android/sizzle/SizzleApp.kt

@@ -0,0 +1,95 @@
+// SPDX-FileCopyrightText: 2026 Reactorcoremeltdown
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package space.rcmd.android.sizzle
+
+import android.app.Application
+import space.rcmd.android.sizzle.audio.AudioEngine
+import space.rcmd.android.sizzle.input.BindingStore
+import space.rcmd.android.sizzle.input.GamepadInput
+import space.rcmd.android.sizzle.input.InputRouter
+import space.rcmd.android.sizzle.input.KeyboardInput
+import space.rcmd.android.sizzle.input.MidiInput
+import space.rcmd.android.sizzle.io.PresetLibrary
+import space.rcmd.android.sizzle.io.ProjectStore
+import space.rcmd.android.sizzle.io.SettingsStore
+import space.rcmd.android.sizzle.io.SongLibrary
+import space.rcmd.android.sizzle.io.ThemeLibrary
+import space.rcmd.android.sizzle.model.Project
+import java.io.File
+import kotlinx.coroutines.runBlocking
+
+/**
+ * The Application object is our (very small) dependency container. Instead of a
+ * DI framework — overkill for a learning-friendly codebase — the handful of
+ * app-wide singletons live here and are reached via `application as SizzleApp`.
+ *
+ * These objects outlive any single screen so playback and input keep working
+ * across rotation and tab switches.
+ */
+class SizzleApp : Application() {
+
+    /** The single in-memory song. Everything edits this one object. */
+    val project: Project by lazy { Project() }
+
+    /** Neutral input bus shared by touch / keyboard / gamepad / MIDI. */
+    val inputRouter: InputRouter by lazy { InputRouter() }
+
+    /** The real-time sound engine (started/stopped by the PlaybackService). */
+    val audioEngine: AudioEngine by lazy { AudioEngine() }
+
+    // Input source handlers are singletons so their (re)bindable maps are shared
+    // between MainActivity (which feeds them hardware events) and the Settings
+    // screen (which edits their bindings via MIDI-learn / gamepad rebind).
+    val keyboardInput: KeyboardInput by lazy { KeyboardInput(inputRouter) }
+    val gamepadInput: GamepadInput by lazy { GamepadInput(inputRouter) }
+    val midiInput: MidiInput by lazy { MidiInput(this, inputRouter) }
+
+    /** Persists the input binding maps across restarts (DataStore-backed). */
+    val bindingStore: BindingStore by lazy { BindingStore(this) }
+
+    /** On-disk instrument/effect preset library in the app's scoped storage. */
+    val presetLibrary: PresetLibrary by lazy { PresetLibrary(File(filesDir, "presets")) }
+
+    /** On-disk `.sng` song library in the app's scoped storage. */
+    val songLibrary: SongLibrary by lazy { SongLibrary(File(filesDir, "songs")) }
+
+    /** On-disk user colour-theme library (`.szt`) in the app's scoped storage. */
+    val themeLibrary: ThemeLibrary by lazy { ThemeLibrary(File(filesDir, "themes")) }
+
+    /** Autosave of the whole project (crash recovery / resume). */
+    val projectStore: ProjectStore by lazy { ProjectStore(File(filesDir, "autosave.sng")) }
+
+    /** App-level settings persistence (theme, audio backend). */
+    val settingsStore: SettingsStore by lazy { SettingsStore(this) }
+
+    override fun onCreate() {
+        super.onCreate()
+        // Crash recovery: restore the last autosaved project before the engine or
+        // UI read it, so a crash / process-death resumes where the user left off.
+        projectStore.restore(project)
+        // Reload the sample audio for any preset-backed Sampler/SoundFont slots —
+        // the autosave keeps file references, not the decoded PCM, so this makes a
+        // selected preset's samples sound again on a fresh start.
+        presetLibrary.rehydrate(project)
+        // Write the built-in factory presets (e.g. the Ambience reverb spaces) to the
+        // on-disk library on first launch so they appear in the standard browser.
+        presetLibrary.seedFactoryPresets()
+        audioEngine.setProject(project)
+        // Restore saved bindings before any hardware event can arrive. This is a
+        // single small read; blocking briefly at cold start keeps the input maps
+        // authoritative from the first keypress rather than racing an async load.
+        runBlocking { bindingStore.loadInto(keyboardInput, gamepadInput, midiInput) }
+        installCrashAutosave()
+    }
+
+    /** Flush an autosave of the current project on any uncaught exception, then let
+     *  the default handler crash/report as usual — so state survives a crash. */
+    private fun installCrashAutosave() {
+        val previous = Thread.getDefaultUncaughtExceptionHandler()
+        Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
+            runCatching { projectStore.save(project) }
+            previous?.uncaughtException(thread, throwable)
+        }
+    }
+}