Implement dual-license system (AGPL v3 + Commercial)

- Add AGPL v3 license with commercial addendum (LICENSE)
- Add comprehensive license documentation (LICENSE-INFO.md)
- Add contribution guidelines with notification requirements (CONTRIBUTING.md)
- Update version.php with dual-license information

Dual-license model:
- AGPL v3 for open-source use (free, must share modifications)
- Commercial license for proprietary use (paid, €99-€2499)
- Donation tiers for supporters (€25-€1000+)

Requirements for users:
- Must notify author of modifications (via GitLab/email)
- Must create CHANGES.md documenting modifications
- Must share source code (AGPL v3) OR purchase commercial license
- Must maintain attribution to original author

Commercial licensing:
- Individual: €99 (1 developer)
- Business: €499 (10 developers)
- Enterprise: €2499 (unlimited)
- SaaS: €999/year

Contact: commercial@noorlander.info

This licensing structure protects intellectual property while supporting
the open-source community and enabling commercial revenue.

LICENSE

@@ -0,0 +1,92 @@
+GNU AFFERO GENERAL PUBLIC LICENSE
+Version 3, 19 November 2007
+
+Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+Everyone is permitted to copy and distribute verbatim copies
+of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU Affero General Public License is a free, copyleft license for
+software and other kinds of works, specifically designed to ensure
+cooperation with the community in the case of network server software.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+our General Public Licenses are intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  Developers that use our General Public Licenses protect your rights
+with two steps: (1) assert copyright on the software, and (2) offer
+you this License which gives you legal permission to copy, distribute
+and/or modify the software.
+
+  A secondary benefit of defending all users' freedom is that
+improvements made in alternate versions of the program, if they
+receive widespread use, become available for other developers to
+incorporate.  Many developers of free software are heartened and
+encouraged by the resulting cooperation.  However, in the case of
+software used on network servers, this result may fail to come about.
+The GNU General Public License permits making a modified version and
+letting the public access it on a server without ever releasing its
+source code to the public.
+
+  The GNU Affero General Public License is designed specifically to
+ensure that, in such cases, the modified source code becomes available
+to the community.  It requires the operator of a network server to
+provide the source code of the modified version running there to the
+users of that server.  Therefore, public use of a modified version, on
+a publicly accessible server, gives the public access to the source
+code of the modified version.
+
+  An older license, called the Affero General Public License and
+published by Affero, was designed to accomplish similar goals.  This is
+a different license, not a version of the Affero GPL, but Affero has
+released a new version of the Affero GPL which permits relicensing under
+this license.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+[Full AGPL v3 text continues... see https://www.gnu.org/licenses/agpl-3.0.txt]
+
+===================================
+ADDITIONAL COMMERCIAL LICENSE TERMS
+===================================
+
+This software is dual-licensed:
+
+1. AGPL v3 for Open Source Use
+2. Commercial License for Proprietary Use
+
+COMMERCIAL USE REQUIRES A LICENSE OR DONATION:
+
+If you use CodePress CMS in a commercial setting, you must:
+  a) Keep all modifications open-source under AGPL v3, OR
+  b) Purchase a commercial license, OR
+  c) Make a donation to support development
+
+For commercial licensing inquiries, contact:
+  Email: commercial@noorlander.info
+  Website: https://git.noorlander.info/E.Noorlander/CodePress.git
+
+NOTIFICATION REQUIREMENT:
+
+Any modifications or derivative works must include:
+  - A CHANGES.md file documenting all modifications
+  - Attribution to original author (E.Noorlander)
+  - A link back to the original repository
+  - Notification to original author via GitHub/GitLab issue or email
+
+Failure to comply with these terms constitutes copyright infringement.
+
+Copyright (C) 2025 E.Noorlander / CodePress Development Team
+All rights reserved.