Add API docs contribution guidance under extend/contribute

extend/contribute/api-docs/checklist.md

@@ -0,0 +1,35 @@
+---
+navigation_title: Checklist
+---
+
+# API docs checklist
+
+Use this checklist to verify the quality, completeness, and consistency of your API docs contributions.
+
+## Content quality and completeness
+
+
+- ☑️ Write clear [summaries](./guidelines.md#write-summaries) (30 characters max, start with a verb)
+- ☑️ Write detailed [descriptions](./guidelines.md#write-descriptions) for operations, parameters, properties, tags etc.
+- ☑️ Document all [path parameters](./guidelines.md#document-path-parameters) with constraints and formats
+- ☑️ Provide descriptions for non-obvious [enum values](./guidelines.md#document-enum-values)
+- ☑️ Specify [default values](./guidelines.md#set-default-values) for optional parameters
+- ☑️ Include realistic [examples](./guidelines.md#add-examples) with helpful descriptions
+- ☑️ Add [links](./guidelines.md#add-links) to related operations and documentation
+
+## Structure, organization, and metadata
+- ☑️ Include required [OpenAPI document info](./organize-annotate.md#add-open-api-document-info)
+- ☑️ Include [OpenAPI specification version](./organize-annotate.md#add-openapi-specification-version)
+- ☑️ Define unique [operation identifiers](./organize-annotate.md#add-operation-identifiers) using camelCase
+- ☑️ Use consistent [tags](./organize-annotate.md#group-apis-with-tags) to group related operations
+- ☑️ Document [API lifecycle status](./organize-annotate.md#specify-api-lifecycle-status) (availability, stability, version information)
+- ☑️ Mark deprecated APIs and properties with appropriate notices
+- ☑️ Document [required permissions](./organize-annotate.md#document-required-permissions) for each operation
+
+## Quality assurance
+
+- ☑️ Preview your changes locally before submitting
+- ☑️ [Lint your API docs](guidelines.md#lint-your-api-docs) to identify and fix issues
+- ☑️ Check all links to ensure they work correctly
+- ☑️ Ensure examples are realistic and error-free
+- ☑️ Validate that your OpenAPI document is well-formed