feat: add docs for the async api

Author: AlbinaBlazhko17

docs/@v2/rules/async/tags-duplicated-names.md

@@ -0,0 +1,92 @@
+# tags-duplicated-names
+
+Ensures that tag names in the `tags` array are unique.
+This rule prevents duplication of tag names which could lead to inconsistent API documentation.
+
+| AsyncAPI | Compatibility |
+| -------- | ------------- |
+| 2.6      | ✅            |
+| 3.0      | ✅            |
+
+## API design principles
+
+Tags are used to group operations in AsyncAPI specifications. Each tag should be unique to clearly categorize operations.
+Having duplicate tags can cause confusion in documentation rendering tools, makes the specification harder to maintain,
+and may lead to operations being grouped incorrectly.
+
+## Configuration
+
+| Option     | Type    | Description                                                                         |
+| ---------- | ------- | ----------------------------------------------------------------------------------- |
+| severity   | string  | Possible values: `off`, `warn`, `error`. Default `warn`.                            |
+| ignoreCase | boolean | Possible values: `true`, `false`. Default `false` (in `recommended` configuration). |
+
+An example configuration:
+
+```yaml
+rules:
+  tags-duplicated-names: error
+```
+
+With ignoring case:
+
+```yaml
+rules:
+  tags-duplicated-names:
+    severity: error
+    ignoreCase: true
+```
+
+## Examples
+
+Given this configuration:
+
+```yaml
+rules:
+  tags-duplicated-names: error
+```
+
+Example of **incorrect** tags:
+
+```yaml Bad example
+tags:
+  - name: pet
+    description: Everything about your Pets
+  - name: store
+    description: Access to Petstore orders
+  - name: store
+    description: Duplicated store tag
+```
+
+Example of **correct** tags:
+
+```yaml Good example
+tags:
+  - name: pet
+    description: Everything about your Pets
+  - name: store
+    description: Access to Petstore orders
+  - name: user
+    description: Operations about user
+```
+
+With **ignoreCase: true**, this would also be incorrect:
+
+```yaml
+tags:
+  - name: pet
+    description: Everything about your Pets
+  - name: store
+    description: Access to Petstore orders
+  - name: Store
+    description: Case-sensitive duplicate
+```
+
+## Related rules
+
+- [tag-description](./tag-description.md)
+
+## Resources
+
+- [Rule source](https://github.com/Redocly/redocly-cli/blob/main/packages/core/src/rules/common/tags-duplicated-names.ts)
+- [Tags docs](https://redocly.com/docs/openapi-visual-reference/tags/)