Add licensing information and update README for KIBU

- Introduced additional terms under Section 7 of the GNU AGPL v3 for KIBU, including attribution, marking of modified versions, and trademark usage.
- Added MIT License file for clarity on licensing options.
- Updated README.md to reflect the new licensing terms, including detailed usage rights and obligations.
- Created REUSE.toml for SPDX compliance and license annotations.
- Added THIRD_PARTY_NOTICES.md to clarify third-party dependencies and their licenses.
- Updated various source files and scripts to include SPDX headers for copyright and licensing.
- Enhanced footer in layout to display licensing information and project link.
- Implemented a new license page to present the AGPL and additional terms clearly.

tests/database.test.ts

@@ -1,3 +1,7 @@
+// SPDX-FileCopyrightText: 2026 Paul Schoeneck
+//
+// SPDX-License-Identifier: AGPL-3.0-only AND LicenseRef-KIBU-Additional-Terms
+
 import "dotenv/config";
 import { after, test } from "node:test";
 import assert from "node:assert/strict";