fix(maestro): keep pane background in the attach snapshot

capture-pane trims trailing spaces, so a line's background stopped at its
last glyph and the client's own background showed through the rest as
stripes. -N keeps the padding, and with it the colour.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

crates/maestro-daemon/src/tmux.rs

@@ -278,6 +278,10 @@ impl Tmux {
                 "capture-pane",
                 "-p",
                 "-e",
+                // Keep trailing spaces, so a line's background colour reaches
+                // the edge instead of stopping at the last glyph and letting
+                // the client's own background show through.
+                "-N",
                 "-t",
                 &name,
                 "-S",