Add contributing guidelines and tweak PR template (#22521)

* add contributing guidelines and modify PR template

* update template

* tweaks

* add note about pinned feature requests

.github/pull_request_template.md

@@ -1,17 +1,17 @@
+_Please read the [contributing guidelines](https://github.com/blakeblackshear/frigate/blob/dev/CONTRIBUTING.md) before submitting a PR._
+
 ## Proposed change
 <!--
   Thank you!
 
+  Describe what this pull request does and how it will benefit users of Frigate.
+  Please describe in detail any considerations, breaking changes, etc.
+
   If you're introducing a new feature or significantly refactoring existing functionality,
   we encourage you to start a discussion first. This helps ensure your idea aligns with
   Frigate's development goals.
-
-  Describe what this pull request does and how it will benefit users of Frigate.
-  Please describe in detail any considerations, breaking changes, etc. that are
-  made in this pull request.
 -->
 
-
 ## Type of change
 
 - [ ] Dependency upgrade
@@ -26,6 +26,44 @@
 - This PR fixes or closes issue: fixes #
 - This PR is related to issue:
 
+## For new features
+
+<!--
+  Every new feature adds scope that maintainers must test, maintain, and support long-term.
+  We try to be thoughtful about what we take on, and sometimes that means saying no to
+  good code if the feature isn't the right fit — or saying yes to something we weren't sure
+  about. These calls are sometimes subjective, and we won't always get them right. We're
+  happy to discuss and reconsider.
+
+  Linking to an existing feature request or discussion with community interest helps us
+  understand demand, but a great idea is a great idea even without a crowd behind it.
+
+  You can delete this section for bugfixes and non-feature changes.
+-->
+
+- [ ] There is an existing feature request or discussion with community interest for this change.
+  - Link:
+
+## AI disclosure
+
+<!--
+  We welcome contributions that use AI tools, but we need to understand your relationship
+  with the code you're submitting. See our AI usage policy in CONTRIBUTING.md for details.
+
+  Be honest — this won't disqualify your PR. Trust matters more than method.
+-->
+
+- [ ] No AI tools were used in this PR.
+- [ ] AI tools were used in this PR. Details below:
+
+**AI tool(s) used** (e.g., Claude, Copilot, ChatGPT, Cursor):
+
+**How AI was used** (e.g., code generation, code review, debugging, documentation):
+
+**Extent of AI involvement** (e.g., generated entire implementation, assisted with specific functions, suggested fixes):
+
+**Human oversight**: Describe what manual review, testing, and validation you performed on the AI-generated portions.
+
 ## Checklist
 
 <!--
@@ -35,5 +73,6 @@
 - [ ] The code change is tested and works locally.
 - [ ] Local tests pass. **Your PR cannot be merged unless tests pass**
 - [ ] There is no commented out code in this PR.
+- [ ] I can explain every line of code in this PR if asked.
 - [ ] UI changes including text have used i18n keys and have been added to the `en` locale.
 - [ ] The code has been formatted using Ruff (`ruff format frigate`)