Fix four quality findings from re-review

sitecustomize.py: exec_module now records a FAIL status when the underlying
module load raises, instead of leaving hook_status.json unwritten. cmd_verify
will now show a diagnostic FAIL rather than the misleading "no status file".

sitecustomize.py: URL-fix loop covers --repository and --repository= in
addition to --repo/--repo=/-r; these are documented restic synonyms.

sitecustomize.py: _replace fallback now catches AttributeError in addition
to TypeError so an unrecognised ResticConfig return type silently falls back
to returning the unmodified result rather than crashing the backup job.

patch_ui.py: warns when FIND.subn produces a count other than 1, making
unexpected multi-replacement visible in the apply log.

uninstall.sh: find for JS bundle restore now includes /usr/share/truenas-ui,
matching all three entries in patch_ui.py's WEBUI_CANDIDATES.

uninstall.sh

@@ -97,7 +97,7 @@ while IFS= read -r backup; do
     mv "$backup" "$original"
     echo "  Restored: $original"
     RESTORED=1
-done < <(find /usr/share/truenas /var/www/truenas \
+done < <(find /usr/share/truenas /usr/share/truenas-ui /var/www/truenas \
               -name "*.js.pre-truecloud-patch" 2>/dev/null)
 
 if [ "$RESTORED" -eq 0 ]; then