Fix Model layer & API robustness batch (7 items) ...

- Entity::update() now checks rowCount; returns false when no rows affected.
- Entity::update() preserves modified_fields on PDOException (try/catch).
- Device::set_device_token() caches auth() call instead of 3 repeated invocations.
- User::__construct() removed eager profile query; profile() now lazy-loads via get_pet_instance().
- alias_is_uniq() in Areas and Devices models accepts optional exclude_id to skip self on update.
- Controllers updated to pass entity id to alias_is_uniq() so updating alias to current value succeeds.
- CronController::run_regular_cron_scripts() wraps each script in try/catch; logs failure and continues.
- App::api_auth_guard() replaced exit() with return false; EventsHandlers stops routing on auth rejection.
- Tests added: EntityCrud (missing-record + preserved-fields), UserEntity (lazy-loading),
  CronController (failure-continuation), AppAuthGuard (structured 401 output),
  Areas/Devices validation (same-alias update allowed).
- Test bootstrap: added logs_enable/logs_folder to FCONF to suppress PHP warnings in Cron tests.

All 136 server tests pass, 334 assertions.
All 167 Vue client tests pass.

Add medium-complexity PHPUnit tests: Area recursion, controller validation ...

- AreaRecursionTest (10 tests): recursive traversal, depth limit ≤10,
  remove() cascade, inner devices/scripts lookup, parent_area()
- AreasRESTAPIControllerValidationTest (10 tests): new_area, update_alias,
  remove_area, place_in_area, update_display_name validation
- DevicesRESTAPIControllerValidationTest (12 tests): setup_new_device,
  do_device_action, update_alias, devices_list, place_in_area validation
- ScriptsRESTAPIControllerValidationTest (10 tests): run_action_script,
  set_*_state, place_in_area validation
- Fix Controller::validate_positive_int_ids() return type: ?array → ?string
- Add DevTools to TestApp/bootstrap for Model instantiation
- Expand bootstrap.php text_msgs with controller error aliases
- Update server-audit.md coverage table: 80 tests, 202 assertions