feat: add offline wake-word detection with sherpa-onnx

- Integrate sherpa-onnx for local "Computer" wake-word detection
- Add foreground service (microphone type) for continued listening across apps
- Request RECORD_AUDIO, POST_NOTIFICATIONS, and foreground service permissions
- Download and verify pinned sherpa-onnx model (17 MB) on first enable
- Update LauncherViewModel with wake-word state and controller
- Add WorkManager and commons-compress dependencies for model extraction
- Update README with wake-word feature details and limitations

settings.gradle.kts

@@ -11,6 +11,14 @@ dependencyResolutionManagement {
     repositories {
         google()
         mavenCentral()
+        ivy {
+            name = "sherpaOnnxReleases"
+            url = uri("https://github.com/k2-fsa/sherpa-onnx/releases/download")
+            patternLayout {
+                artifact("v[revision]/[artifact]-[revision].[ext]")
+            }
+            metadataSources { artifact() }
+        }
     }
 }