Normalize shell and patch tool cards

app/androidApp/src/test/kotlin/com/example/aiapp/HighlighterTest.kt

@@ -338,6 +338,21 @@ class HighlighterTest {
         assertEquals("+[-]", highlight("+[-]", fenceLanguage("brainfuck")).text)
     }
 
+    @Test
+    fun `a diff colours changes and identifies its framing separately`() {
+        val code = "--- a/file\n+++ b/file\n@@ -1 +1 @@\n-old\n context\n+new"
+        assertSpans(code, Language.DIFF, Kind.DELETION, "-old")
+        assertSpans(code, Language.DIFF, Kind.ADDITION, "+new")
+        assertSpans(
+            code,
+            Language.DIFF,
+            Kind.METADATA,
+            "--- a/file",
+            "+++ b/file",
+            "@@ -1 +1 @@",
+        )
+    }
+
     @Test
     fun `every language the fence table knows has a scanner`() {
         Language.entries.forEach { spansOf("x", it) }