fix: silent exit on permission denied during App State Cleanup (#438)

[spider-yamet]

Fixes #438

Problem

mo optimize exits with code 1 during "App State Cleanup" when it hits a .savedState directory that needs Full Disk Access (e.g. net.maxon.appinstaller.savedState). With set -euo pipefail, the failing safe_remove stops the script instead of skipping the protected directory.

Solution

Add || true after safe_remove calls in opt_saved_state_cleanup and opt_cache_refresh, matching the Pipefail Safety pattern in CONTRIBUTING.md:

All commands that might fail must be handled

find /nonexistent -name "*.cache" 2>/dev/null || true