chore: add 'set -e' to every nomarchy-* bash script that lacks it

Sweep across the three script directories: features/scripts/utils,
core/system/scripts, themes/engine/scripts. 142 of 169 bash scripts
gained `set -e`; 27 already had it; the one Python helper
(nomarchy-haptic-touchpad) was skipped via shebang detection.

Why: bash's default behavior is to continue past a failed command,
which means a script that does "do A; do B; do C" leaves the system
in a half-applied state when B fails - and the user gets no signal.
Several recent fix commits (theme partial-apply, waybar reload race,
installer prewipe silent failures) all trace back to this. set -e
turns silent corruption into a loud abort the user can act on.

The 11 scripts with explicit `|| true` markers stay safe under set -e
because || true coerces the exit to zero; the markers continue to
mean "I deliberately tolerate this failure here."

Deliberate exception: nomarchy-menu runs WITHOUT set -e. It is an
interactive UX loop where action branches do `cmd; back_to <self>`
so a failed action would abort the script under set -e and the menu
would disappear without feedback. Soft-failure - menu re-displays,
user picks again - is the right semantic. Documented inline.

Validation: bash -n on every modified script (zero failures). The
new pre-commit hook (27f5663) was just updated to filter by shebang
so it doesn't try to bash-syntax-check the Python helper - that
filter was uncovered by this sweep.

Risk: set -e can surface latent bugs in scripts that previously
relied on silent continuation. If anything breaks, it's a real bug
that was already broken and is now visible. Easy per-script revert
if any UX glitches show up.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

themes/engine/scripts/nomarchy-show-done

@@ -1,4 +1,5 @@
 #!/bin/bash
+set -e
 
 # Display a "Done!" message with a spinner and wait for user to press any key.
 # Used by various install scripts to indicate completion.