fix(userMessageDisplay): paint wrapped lines with the configured bg by finalizing boxAttrs after the bg block

Reported: with custom User Message Display settings, a message long enough
to wrap in the terminal had its highlight only on line 1 — line 2+ rendered
against the terminal default bg.
Two bugs collided to cause this:
1. Latent ordering bug: `boxAttrsObjStr` was computed right after the
   padding/border block, before the foreground/background block ran. Every
   `boxAttrs.push('backgroundColor:...')` afterwards — including the default-
   branch push added in 3114c5b — was silently discarded. So even with
   `backgroundColor: 'default'` the Box had no bg; only the inner Text's
   theme token was in play, and Ink's Text bg applies to the text cells
   but doesn't fill the padded Box width on wrapped lines.
2. For a custom bg (`rgb(r,g,b)`) the patch was only adding `.bgRgb()` to
   the chalk chain. That wraps the text content in ANSI bg escapes, but
   when Ink word-wraps the message the escape on line 1 doesn't reliably
   re-open on line 2, leaving wrapped lines bare.
Fixes:
- Move `boxAttrsObjStr` finalization to after the bg block so every push
  (default-theme token and custom rgb) reaches the emitted element attrs.
- For custom bg, also push `backgroundColor:"rgb(r,g,b)"` onto boxAttrs
  and textAttrs alongside the existing chalk.bgRgb chain. Box-level bg is
  what actually fills the padded width across every wrapped line; Text-
  level bg covers the text cells where chalk's state may have been reset.
Verified against CC 2.1.112 cli.js — emitted shapes:
  default bg:  Box{paddingRight:1,backgroundColor:"userMessageBackground"}
               Text{color:"text",backgroundColor:"userMessageBackground"}
  custom bg:   Box{paddingRight:1,backgroundColor:"rgb(200,80,40)"}
               Text{color:"text",backgroundColor:"rgb(200,80,40)"}
               chalk.bgRgb(200,80,40)(...)
  null bg:     Box{paddingRight:1}  Text{color:"text"}  (unchanged)
Ink's `colorize.js` accepts `"rgb(r,g,b)"` (no spaces) which is exactly
what the `\d+` regex + join produces, even if the input has spaces.
All 228 tests still pass.

Author: Ben

src/patches/userMessageDisplay.ts

@@ -222,8 +222,9 @@ export const writeUserMessageDisplay = (
     boxAttrs.push(`alignSelf:"flex-start"`);
   }
 
-  const boxAttrsObjStr =
-    boxAttrs.length > 0 ? `{${boxAttrs.join(',')}}` : 'null';
+  // Note: boxAttrsObjStr is finalized further below, after the bg block. The
+  // bg handling pushes onto boxAttrs so the Box fills wrapped lines across
+  // the full width — finalizing here would silently drop those pushes.
 
   // Build chalk chain for custom colors and styling, plus any Text-level
   // theme tokens for 'default' fg/bg (ink Text props apply theme colors
@@ -248,6 +249,17 @@ export const writeUserMessageDisplay = (
     const bgMatch = config.backgroundColor.match(/\d+/g);
     if (bgMatch) {
       chalkChain += `.bgRgb(${bgMatch.join(',')})`;
+      // Also apply the bg at the Ink level. chalk's ANSI bg codes live inside
+      // the text content, and when Ink word-wraps the message the escape on
+      // line 1 doesn't reliably re-open on line 2 — so a message that wraps
+      // renders with a highlighted first line and a bare (terminal-default)
+      // second line. Pushing the color onto the Box (fills the padded width
+      // across every wrapped line) and onto the inner Text (covers the text
+      // cells themselves where chalk's state may have been reset) keeps the
+      // highlight consistent across the whole wrapped block.
+      const inkBg = `"rgb(${bgMatch.join(',')})"`;
+      boxAttrs.push(`backgroundColor:${inkBg}`);
+      textAttrs.push(`backgroundColor:${inkBg}`);
     }
   } else if (config.backgroundColor === 'default') {
     // Stock CC 2.1.79+ renders user messages inside a Box with
@@ -297,6 +309,12 @@ export const writeUserMessageDisplay = (
 
   const chalkFormattedString = `${chalkChain}(${formattedMessage})`;
 
+  // Finalize the Box/Text attrs AFTER the bg block above has had a chance
+  // to push onto them. Doing this earlier (e.g. right after the padding
+  // block) would silently drop every bg push — which is what caused
+  // wrapped user messages to lose their highlight on line 2+.
+  const boxAttrsObjStr =
+    boxAttrs.length > 0 ? `{${boxAttrs.join(',')}}` : 'null';
   const textAttrsObjStr =
     textAttrs.length > 0 ? `{${textAttrs.join(',')}}` : 'null';