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.

REUSE.toml

@@ -0,0 +1,17 @@
+# SPDX-FileCopyrightText: 2026 Paul Schoeneck
+#
+# SPDX-License-Identifier: AGPL-3.0-only AND LicenseRef-KIBU-Additional-Terms
+
+version = 1
+
+[[annotations]]
+path = ["package.json", "package-lock.json", "tsconfig.json", "LICENSE"]
+precedence = "aggregate"
+SPDX-FileCopyrightText = "2026 Paul Schoeneck"
+SPDX-License-Identifier = "AGPL-3.0-only AND LicenseRef-KIBU-Additional-Terms"
+
+[[annotations]]
+path = "next-env.d.ts"
+precedence = "aggregate"
+SPDX-FileCopyrightText = "2025 Vercel, Inc."
+SPDX-License-Identifier = "MIT"