fix: installer wrote "bash \~/.claude/statusline.sh" with backslash

The parameter expansion ${DEST/#$HOME/\~} escaped the tilde,
producing a literal backslash in settings.json. Tilde stored in a
variable avoids both backslash-escaping and tilde-expansion.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: lroolle

install.sh

@@ -20,7 +20,8 @@ curl -fsSL "${RAW}/statusline.sh" -o "$DEST"
 chmod +x "$DEST"
 info "Installed to $DEST"
 
-STATUSLINE_CMD="bash ${DEST/#$HOME/\~}"
+_tilde='~'
+STATUSLINE_CMD="bash ${DEST/#$HOME/$_tilde}"
 
 if [ ! -f "$SETTINGS" ]; then
     info "Creating $SETTINGS"