docs: create release notes for TypeSpec 1.11.0 (#10286)

Release notes for the upcoming 1.11.0 release, generated from pending
`.chronus/changes/` entries for the `typespec-stable` and
`typespec-preview` version policies per CONTRIBUTING.md.

Note: `pnpm chronus changelog` could not be used directly (GitHub API
unavailable in this environment), so PR numbers were resolved from git
history manually.

### Contents

- **Features**: `@typespec/compiler` — new `FilterVisibility` template
replacing the now-deprecated `@withVisibilityFilter` decorator
- **Bug Fixes**:
- `@typespec/compiler` — model name in `duplicate-property` errors,
union name in `duplicateDefaultVariant`, non-primitive config
interpolation fix, template parameter value assignment fix
- `@typespec/openapi3` — importer `anyOf` with `$ref` + inline object,
"Duplicate type name" for named union with `bytes` in multipart body

Internal and dependency-only changes excluded per convention.

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: timotheeguerin <1031227+timotheeguerin@users.noreply.github.com>

Author: Copilot

website/src/content/docs/release-notes/typespec-1-11-0.md

@@ -0,0 +1,33 @@
+---
+slug: release-notes/typespec-1-11-0
+title: "1.11.0"
+releaseDate: 2026-04-07
+version: "1.11.0"
+---
+
+# 1.11.0
+
+## Features
+
+### @typespec/compiler
+
+- [#9893](https://github.com/microsoft/typespec/pull/9893) Added a new template `FilterVisibility` to support more accurate visibility transforms. This replaces the `@withVisibilityFilter` decorator, which is now deprecated and slated for removal in a future version of TypeSpec.
+
+## Bug Fixes
+
+### @typespec/compiler
+
+- [#10196](https://github.com/microsoft/typespec/pull/10196) Include model name in `duplicate-property` error message
+- [#10199](https://github.com/microsoft/typespec/pull/10199) `duplicateDefaultVariant` diagnostic now includes the union type name
+- [#10183](https://github.com/microsoft/typespec/pull/10183) Do not interpolate non primitive values in config automatically.
+  ```yaml
+  file-type: ["json", "yaml"]
+  output-file: "openapi.{file-type}"
+  ```
+  Will not be interpolated as `openapi.json,yaml` but keep the placeholder `{file-type}` intact for the emitter to handle.
+- [#9893](https://github.com/microsoft/typespec/pull/9893) Fixed a bug that would prevent template parameters from assigning to values in some cases.
+
+### @typespec/openapi3
+
+- [#10041](https://github.com/microsoft/typespec/pull/10041) [importer] Fix `anyOf` with `$ref` and inline object being incorrectly imported as a model instead of a union.
+- [#10046](https://github.com/microsoft/typespec/pull/10046) Fix OpenAPI emitter failing with "Duplicate type name" error when using a named union with a `bytes` variant in a multipart body (e.g. `HttpPart<MyUnion>` where `MyUnion` includes `bytes`).