fix: align wrap mode with Ink (trim: false)

Ink's wrap mode uses { trim: false } to preserve leading/trailing
whitespace on wrapped lines. We incorrectly used trim: true which
stripped whitespace. Updates unit test and inline snapshots.

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

packages/runtime-tests/integration/components/background-color.test.tsx

@@ -115,8 +115,8 @@ test("Multiple Text elements inherit same background", async () => {
     { columns: 100 },
   );
   expect(lastFrame()).toMatchInlineSnapshot(`
-    "Hello
-    World"
+    "Hello 
+    World "
   `);
 });
 
@@ -132,9 +132,9 @@ test("Mixed text with and without background inheritance", async () => {
     { columns: 100 },
   );
   expect(lastFrame()).toMatchInlineSnapshot(`
-    "Inherited
-    No BG    
-    Red BG   "
+    "Inherited 
+    No BG     
+    Red BG    "
   `);
 });
 
@@ -154,8 +154,8 @@ test("Complex nested structure with background inheritance", async () => {
     { columns: 100 },
   );
   expect(lastFrame()).toMatchInlineSnapshot(`
-    "Outer:  
-    Inner:  
+    "Outer:  
+    Inner:  
     Explicit"
   `);
 });
@@ -422,7 +422,7 @@ test("Box backgroundColor fills full width on every line when text wraps", async
     { columns: 100 },
   );
   expect(lastFrame()).toMatchInlineSnapshot(`
-    "Hello     
+    "Hello     
     World!!   "
   `);
 });
@@ -437,7 +437,7 @@ test("Text-only backgroundColor colors text content but does not fill Box width"
     { columns: 100 },
   );
   expect(lastFrame()).toMatchInlineSnapshot(`
-    "Hello
+    "Hello 
     World!!"
   `);
 });