perf(backup): drop sudo overhead from sourceBackupLocations (Phase 6)

The location_loader's find ran through runFileOp (sudo -u libreportal),
which forks a sudo shell purely for the find call. configs/backup/
locations/ is already manager-owned (not in the dockerinstall-owned
containers tree), so the sudo step adds ~50 ms of process-creation
overhead for zero security benefit.

Plain `find` now, with a tiny [[ ! -r || ! -x ]] guard that falls
back to runFileOp if someone relocates the dir to a non-traversable
location. Same observable behaviour, ~50 ms saved per CLI invocation.

This is the simpler half of Phase 6 — the libreportal_configs scan
itself was already plain-find (only ~11 ms total for 22 files). The
remaining costly scan is app_configs against /libreportal-containers/,
which legitimately needs sudo because dockerinstall owns that tree.
Precompiling its content is possible but adds invalidation complexity
(updateConfigOption writes happen at runtime) — deferred for now;
better return on simpler interventions.

Signed-off-by: librelad <librelad@digitalangels.vip>

scripts/backup/locations/location_loader.sh

@@ -11,8 +11,18 @@ sourceBackupLocations()
     dir=$(backupLocationsDir)
     [[ ! -d "$dir" ]] && return 0
 
+    # configs/backup/locations/ lives in the manager-owned configs tree (not
+    # the dockerinstall-owned containers tree), so a plain find works fine.
+    # runFileOp was adding ~50 ms of sudo-shell overhead per invocation for
+    # no benefit. Fall back to runFileOp only if the directory isn't readable
+    # for some reason (relocated tree, custom permissions, …).
+    local find_cmd=(find)
+    if [[ ! -r "$dir" || ! -x "$dir" ]] && declare -f runFileOp >/dev/null 2>&1; then
+        find_cmd=(runFileOp find)
+    fi
+
     local cfg
     while IFS= read -r -d '' cfg; do
         [[ -f "$cfg" ]] && source "$cfg"
-    done < <(runFileOp find "$dir" -mindepth 2 -maxdepth 2 -name location.config -type f -print0 2>/dev/null)
+    done < <("${find_cmd[@]}" "$dir" -mindepth 2 -maxdepth 2 -name location.config -type f -print0 2>/dev/null)
 }