Clarify contributing policy

.github/pull_request_template.md

@@ -0,0 +1,9 @@
+# Pull Request Checklist
+
+Please read our latest [CONTRIBUTING.md](https://github.com/royshil/obs-backgroundremoval/blob/main/CONTRIBUTING.md).
+
+- [ ] I have read the latest CONTRIBUTING.md.
+- [ ] I have acknowledged the licensing and patent grant policy.
+- [ ] I have included the required license headers.
+- [ ] I am confident with my code integrity.
+- [ ] I have signed off and verified all my commits.

.gitignore

@@ -20,6 +20,7 @@
 !buildspec.json
 !CMakeLists.txt
 !CMakePresets.json
+!CONTRIBUTING.md
 !FAQ.md
 !LICENSE
 !README.md

CONTRIBUTING.md

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+# CONTRIBUTING.md for obs-backgroundremoval
+
+## Legal and Community Guidelines
+
+To keep the `obs-backgroundremoval` project safe and reliable for everyone including its users, its contributors, and its maintainers, those who are involved in development of this project must know the following terms. Whenever we receive your Pull Request, we will explicitly ask you that your PRs conform to our policy.
+
+### 1. Licensing and Patent Grant
+
+- **GPL-3.0-or-later**: You agree to distribute your contribution under the GNU General Public License v3.0 or later.
+- **Patent License**: Refer to the [terms of GNU GPLv3 (Section 11)](https://www.gnu.org/licenses/gpl-3.0.html#section11) about patents.
+
+### 2. License Headers
+
+To ensure the transparency of our codebase, we require all new code to include the following header. Please provide the year you wrote this code, your full legal name, and your email address associated with your GitHub account.
+
+```cpp
+/*
+ * SPDX-FileCopyrightText: Copyright (C) [Year] [Author Name] [Email]
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * OBS Plugin: Portrait Background Removal / Virtual Green-screen and Low-Light Enhancement
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+```
+
+### 3. Code Integrity
+
+We always welcome every contribution! To deliver the value of your work to our users in a professional manner, please adhere to the following policies:
+
+- **No Unverified Code**: Do not submit any code that you cannot fully understand and explain. Submitting any raw outputs from LLMs or Generative-AI is strictly prohibited.
+- **Responsibility**: You must take responsibility for your code. Please ensure that your contribution has clean licensing and is reliable. We are here to help you to accomplish this, of course!
+
+### 4. Developer Certificate of Origin (DCO) and Commit Signing
+
+Please sign off (Developer Certificate of Origin) and verify all your commits:
+
+```
+git commit -s -S
+```
+
+If you want to sign off your commits in our repository automatically:
+
+```
+git config format.signOff true
+```
+
+For details of commit signing, please refer to the [GitHub Document for commit signing](https://docs.github.com/authentication/managing-commit-signature-verification).