P6 Stream V: ImageCompression (expect/actual) + CameraPicker polish

Android: BitmapFactory + ExifInterface + JPEG quality 0.7 + 1920px downscale.
iOS: UIImage.jpegData. JVM/JS/WASM: no-op. CameraPicker uses TakePicture
ActivityResult + permission rationale.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

composeApp/src/jvmMain/kotlin/com/tt/honeyDue/util/ImageCompression.jvm.kt

@@ -0,0 +1,18 @@
+package com.tt.honeyDue.util
+
+/**
+ * JVM / Desktop no-op implementation of [ImageCompression].
+ *
+ * Image compression on Desktop is not exercised by the app today — uploads
+ * happen from mobile only. Returning the input unchanged keeps call sites
+ * in common code compiling and functional (the server accepts the raw
+ * bytes at worst). Replace with an ImageIO/TwelveMonkeys pipeline if this
+ * path is ever needed.
+ */
+actual object ImageCompression {
+    actual suspend fun compress(
+        input: ByteArray,
+        maxEdgePx: Int,
+        quality: Float
+    ): ByteArray = input
+}