Split user-level setup into bin/omarchy-setup-user

User-level files (~/.config, ~/.local/share, ~/.agents, etc.) shouldn't
be written by install.sh — it runs as root or with system-level sudo,
and in offline (ISO chroot) mode the user doesn't exist yet. Moved into
a per-user idempotent command, called from omarchy-first-run.

Moved into bin/omarchy-setup-user (deleted from install/config/):
- omarchy-ai-skill.sh    AI skill symlinks
- omarchy-toggles.sh     hypr toggle flags
- nautilus-python.sh     nautilus extensions
- branding.sh            ~/.config/omarchy/branding/{about,screensaver}.txt
- user-dirs.sh           xdg-user-dirs-update + gtk bookmarks
- detect-keyboard-layout.sh  layout/variant sed into ~/.config/hypr/input.lua
- toggles.sh             ~/.local/state/omarchy/toggles mkdir
- mimetypes.sh           omarchy-refresh-applications + xdg-mime/xdg-settings

Kept in install/config/ (rely on OMARCHY_USER_NAME / OMARCHY_USER_EMAIL
that only exist during install):
- git.sh        git config --global user.{name,email}
- xcompose.sh   ~/.XCompose with name/email substituted

omarchy-setup-user:
- Refuses to run as root
- Idempotent via ~/.local/state/omarchy/setup-user.done marker
- --force escape hatch for re-running after dev-link or upstream changes
- Defaults OMARCHY_PATH to /usr/share/omarchy so it works outside install

bin/omarchy-first-run now invokes omarchy-setup-user unconditionally
(it self-gates), so first user login picks up the user setup.

install/config/all.sh: dropped the eight deleted entries.

All three packages (omarchy, omarchy-settings, omarchy-installer) still
build clean.

install/config/all.sh

@@ -1,5 +1,4 @@
 run_logged $OMARCHY_INSTALL/config/theme.sh
-run_logged $OMARCHY_INSTALL/config/branding.sh
 run_logged $OMARCHY_INSTALL/config/git.sh
 run_logged $OMARCHY_INSTALL/config/gpg.sh
 run_logged $OMARCHY_INSTALL/config/increase-lockout-limit.sh
@@ -7,21 +6,14 @@ run_logged $OMARCHY_INSTALL/config/lockscreen-pam.sh
 run_logged $OMARCHY_INSTALL/config/sleep-lock.sh
 run_logged $OMARCHY_INSTALL/config/increase-file-watchers.sh
 run_logged $OMARCHY_INSTALL/config/increase-fd-limit.sh
-run_logged $OMARCHY_INSTALL/config/detect-keyboard-layout.sh
 run_logged $OMARCHY_INSTALL/config/xcompose.sh
 run_logged $OMARCHY_INSTALL/config/mise-work.sh
 run_logged $OMARCHY_INSTALL/config/fix-powerprofilesctl-shebang.sh
 run_logged $OMARCHY_INSTALL/config/docker.sh
-run_logged $OMARCHY_INSTALL/config/mimetypes.sh
-run_logged $OMARCHY_INSTALL/config/user-dirs.sh
-run_logged $OMARCHY_INSTALL/config/toggles.sh
-run_logged $OMARCHY_INSTALL/config/nautilus-python.sh
 run_logged $OMARCHY_INSTALL/config/localdb.sh
 run_logged $OMARCHY_INSTALL/config/fast-shutdown.sh
 run_logged $OMARCHY_INSTALL/config/input-group.sh
-run_logged $OMARCHY_INSTALL/config/omarchy-ai-skill.sh
 run_logged $OMARCHY_INSTALL/config/pi.sh
-run_logged $OMARCHY_INSTALL/config/omarchy-toggles.sh
 run_logged $OMARCHY_INSTALL/config/powerprofilesctl-rules.sh
 run_logged $OMARCHY_INSTALL/config/wifi-powersave-rules.sh