chore: Update copyright year from 2025 to 2026 across core files

- Updated copyright headers in 3,055 core application files
- Changed 'Copyright (C) 2014-2025' to 'Copyright (C) 2014-2026'
- Added 123 new files from EspoCRM core updates
- Removed 4 deprecated files
- Total changes: 61,637 insertions, 54,283 deletions

This is a routine maintenance update for the new year 2026.

data/.backup/upgrades/6984c60172a117840/files/application/Espo/Resources/texts/about.md

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+## EspoCRM – Open Source CRM application
+
+www.espocrm.com
+
+Copyright © 2014-2025 EspoCRM, Inc.
+
+EspoCRM is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+
+EspoCRM is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License along with EspoCRM. If not, see https://www.gnu.org/licenses/.
+
+The interactive user interfaces in modified source and object code versions of this program must display Appropriate Legal Notices, as required under Section 5 of the GNU Affero General Public License version 3.
+
+In accordance with Section 7(b) of the GNU Affero General Public License version 3, these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+
+---
+
+Authors: Yurii Kuznietsov, Taras Machyshyn, Oleksii Avramenko.