ASCII-only spinner frames and output (VM locale rendered braille as garbage)

The braille spinner frames and the em-dash separator are multibyte
UTF-8; on the VM session they rendered as changing random letters, not
a spinner. Frames are now the classic | / - \ cycle, the separator is
':', and the two user-facing info lines that carried em-dashes are
ASCII too. Verified under LANG=C LC_ALL=C in a pty: zero non-ASCII
bytes in the entire output.

lib/common.sh

@@ -107,14 +107,17 @@ ui_quiet_run() {
     # animates independently of gum and shows real progress, not just motion.
     "$@" >>"$log" 2>&1 &
     local pid=$!
-    local frames=( '⠋' '⠙' '⠹' '⠸' '⠼' '⠴' '⠦' '⠧' '⠇' '⠏' )
+    # ASCII frames ONLY: braille/em-dash are multibyte UTF-8 and rendered as
+    # garbage letters when the session locale is not UTF-8 (VM-proven: the
+    # spinner appeared as changing random chars, not as a spinner).
+    local frames=( '|' '/' '-' '\\' )
     local f=0 cur
     while kill -0 "$pid" 2>/dev/null; do
         cur=$(sed -n "$((before+1)),\$p" "$log" 2>/dev/null \
                 | grep -E '^(Installing|Upgrading|Downgrading|Removing|Verifying|Preparing|Cleanup):' \
                 | tail -n 1 || true)
         if [[ -n "$cur" ]]; then
-            printf '\r  %s %s — %s' "${frames[$f]}" "$msg" "$cur" >&2
+            printf '\r  %s %s: %s' "${frames[$f]}" "$msg" "$cur" >&2
         else
             printf '\r  %s %s' "${frames[$f]}" "$msg" >&2
         fi