chore(scripts): remove unused VERBOSE declarations

Remove VERBOSE="${VERBOSE:-0}" from scripts that never reference
$VERBOSE after setting it. The variable is already set in
scripts/shared.sh line 5.

scripts/install-python-packages.sh

@@ -5,9 +5,6 @@ set -euo pipefail
 # shellcheck source=shared.sh
 source "$DOTFILES/config/shared.sh"
 
-# Enable verbosity with VERBOSE=1
-VERBOSE="${VERBOSE:-0}"
-
 msgr run "Starting to install Python packages"
 
 # Ensure uv is available