Chat bubbles: render markdown (bold/italic/tables/syntax-highlighted code) for agent + user messages; tap-to-copy inline code with flash, code-block copy button; preserve user newlines; removed stale HANDOFF doc

app/shared/src/commonTest/kotlin/iris/util/MarkdownTest.kt

@@ -0,0 +1,42 @@
+package iris.util
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class MarkdownTest {
+
+    @Test
+    fun stripsLeadingNewlines() {
+        assertEquals("Hello", "\n\nHello".prepareForMarkdown())
+        assertEquals("Hello", "\nHello".prepareForMarkdown())
+        assertEquals("Hello", "\r\n\r\nHello".prepareForMarkdown())
+    }
+
+    @Test
+    fun stripsLeadingBlankLines() {
+        assertEquals("Hello", "\n   \n\t\nHello".prepareForMarkdown())
+        assertEquals("a\nb", "\n\na\nb".prepareForMarkdown())
+    }
+
+    @Test
+    fun preservesLeadingIndentationOnFirstLine() {
+        // An indented code block at the very start must still parse as code.
+        assertEquals("    code", "\n\n    code".prepareForMarkdown())
+    }
+
+    @Test
+    fun leavesInteriorWhitespaceUntouched() {
+        val md = "Line one\n\nLine two\n\n- item"
+        assertEquals(md, md.prepareForMarkdown())
+    }
+
+    @Test
+    fun noLeadingNewlinesIsUnchanged() {
+        assertEquals("Hello world", "Hello world".prepareForMarkdown())
+    }
+
+    @Test
+    fun allBlankBecomesEmpty() {
+        assertEquals("", "\n\n   \n".prepareForMarkdown())
+    }
+}