Composable Preferences rewrite (#1277)

* Remove ContributionManager and ContributionPane UI files

Deleted ContributionManager.kt and ContributionPane.kt from the contrib/ui directory. This removes the Compose-based contributions manager and its detail pane prototypes which got merged unnecessarily

* Enhance Preferences reactivity and test coverage

Refactored ReactiveProperties to use snapshotStateMap for Compose reactivity. Improved PreferencesProvider and watchFile composables with better file watching, override support via system properties, and added documentation. Updated PreferencesKtTest to use temporary files and verify file-to-UI reactivity.

* Small bugfix for removed function

* Add compose ui test to the deps

Author: Stefterv

app/test/processing/app/PreferencesKtTest.kt

@@ -0,0 +1,61 @@
+package processing.app
+
+import androidx.compose.material.Button
+import androidx.compose.material.Text
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.test.*
+import java.util.Properties
+import kotlin.io.path.createFile
+import kotlin.io.path.createTempDirectory
+import kotlin.test.Test
+
+class PreferencesKtTest{
+    @OptIn(ExperimentalTestApi::class)
+    @Test
+    fun testKeyReactivity() = runComposeUiTest {
+        val directory = createTempDirectory("preferences")
+        val tempPreferences = directory
+            .resolve("preferences.txt")
+            .createFile()
+            .toFile()
+
+        // Set system properties for testing
+        System.setProperty("processing.app.preferences.file", tempPreferences.absolutePath)
+        System.setProperty("processing.app.preferences.debounce", "0")
+        System.setProperty("processing.app.watchfile.forced", "true")
+
+        val newValue = (0..Int.MAX_VALUE).random().toString()
+        val testKey = "test.preferences.reactivity"
+
+        setContent {
+            PreferencesProvider {
+                val preferences = LocalPreferences.current
+                Text(preferences[testKey] ?: "default", modifier = Modifier.testTag("text"))
+
+                Button(onClick = {
+                    preferences[testKey] = newValue
+                }, modifier = Modifier.testTag("button")) {
+                    Text("Change")
+                }
+            }
+        }
+
+        onNodeWithTag("text").assertTextEquals("default")
+        onNodeWithTag("button").performClick()
+        onNodeWithTag("text").assertTextEquals(newValue)
+
+        val preferences = Properties()
+        preferences.load(tempPreferences.inputStream().reader(Charsets.UTF_8))
+
+        // Check if the preference was saved to file
+        assert(preferences[testKey] == newValue)
+
+
+        val nextValue = (0..Int.MAX_VALUE).random().toString()
+        // Overwrite the file to see if the UI updates
+        tempPreferences.writeText("$testKey=${nextValue}")
+
+        onNodeWithTag("text").assertTextEquals(nextValue)
+    }
+}