Release prep for 1.21.0 (#4972)

* Release prep for 1.21.0

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Various changelog improvements and update NOTICE

* Change to errors

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: MicroFish91

CHANGELOG.md

@@ -1,24 +1,39 @@
 # Change Log
 
-## 1.21.0 - 2026-04-03
+## 1.21.0 - 2026-04-14
+
+### Overview
+This release brings DTS consumption plan support, a new Function Host Debugger View with Copilot support, domain name label scope support, and includes several bug fixes for scheduler creation, .NET templates, and containerized deployments.
 
 ### Added
-* [[4883](https://github.com/microsoft/vscode-azurefunctions/pull/4883)] Add a **Function Host Debug** view in the Run and Debug panel that lists running Function Host tasks, displays recent error output, and send errors to Copilot or provides commands to view logs
-* [[4909](https://github.com/microsoft/vscode-azurefunctions/pull/4909)] Support for domain name label scopes
+* [[4951](https://github.com/microsoft/vscode-azurefunctions/pull/4951)] Support **DTS consumption plan** and remove preview flag
+* [[4883](https://github.com/microsoft/vscode-azurefunctions/pull/4883)] Add **Function Host Debugger View** — captures `func` CLI errors in a dedicated section of the Debug panel and lets you ask Copilot for help directly from the view
+* [[4909](https://github.com/microsoft/vscode-azurefunctions/pull/4909)] Support **domain name label scopes**
 
 ### Changed
+* [[4946](https://github.com/microsoft/vscode-azurefunctions/pull/4946)] Open sample file and `mcp.json` in split editor when creating **Self-Hosted MCP Server** projects
+* [[4902](https://github.com/microsoft/vscode-azurefunctions/pull/4902)] Auto-open `mcp.json` after **Self-Hosted MCP Server** project creation
+* [[4944](https://github.com/microsoft/vscode-azurefunctions/pull/4944)] Remove `proxies.json` JSON schema contribution
 * [[4826](https://github.com/microsoft/vscode-azurefunctions/pull/4826)] Group templates by filter rather than filtering them out
-* [[4892](https://github.com/microsoft/vscode-azurefunctions/pull/4892)] Use StorageV2 for storage account creation
-* [[4902](https://github.com/microsoft/vscode-azurefunctions/pull/4902)] Auto-open `mcp.json` after Self-Hosted MCP Server project creation
+* [[4892](https://github.com/microsoft/vscode-azurefunctions/pull/4892)] Use **StorageV2** for storage account creation
+* [[4901](https://github.com/microsoft/vscode-azurefunctions/pull/4901)] Respect **Java remote debugging** setting precedence when both debug modes are enabled
+* [[4923](https://github.com/microsoft/vscode-azurefunctions/pull/4923)] Improve extension responsiveness in common Azure Functions workflows
+* [[4954](https://github.com/microsoft/vscode-azurefunctions/pull/4954)] Update aka.ms link for Remote Debugging
 
 ### Fixed
+* [[4963](https://github.com/microsoft/vscode-azurefunctions/pull/4963)] Fix and improve scheduler creation with **consumption SKU**
+* [[4929](https://github.com/microsoft/vscode-azurefunctions/pull/4929)] Fix fallback to storage suffix endpoint when not available
+* [[4915](https://github.com/microsoft/vscode-azurefunctions/pull/4915)] Fix not being able to get **.NET** latest templates
+* [[4914](https://github.com/microsoft/vscode-azurefunctions/pull/4914)] Fix no response when executing **Create New Project** command
 * [[4880](https://github.com/microsoft/vscode-azurefunctions/pull/4880)] Fix refresh error on collapsed function app nodes
-* [[4901](https://github.com/microsoft/vscode-azurefunctions/pull/4901)] Respect Java remote debugging setting precedence when both debug modes are enabled
-* [[4914](https://github.com/microsoft/vscode-azurefunctions/pull/4914)] Fix no response when executing "Create New Project" command
-* [[4915](https://github.com/microsoft/vscode-azurefunctions/pull/4915)] Fix not being able to get .NET latest templates
-* [[4923](https://github.com/microsoft/vscode-azurefunctions/pull/4923)] Performance improvements
-* [[4929](https://github.com/microsoft/vscode-azurefunctions/pull/4929)] Don't call for `storageConnectionString` if it's not needed
-* [[4944](https://github.com/microsoft/vscode-azurefunctions/pull/4944)] Remove `proxies.json` from JSON schema contribution
+* [[4770](https://github.com/microsoft/vscode-azurefunctions/pull/4770)] Pin EventGrid sample files URL to specific commit SHA
+
+### Engineering
+* [[4947](https://github.com/microsoft/vscode-azurefunctions/pull/4947)] Replace **JsonCli** tool with direct nupkg parsing and native `dotnet new`
+* [[4894](https://github.com/microsoft/vscode-azurefunctions/pull/4894)] Migrate to **esbuild**
+* [[4906](https://github.com/microsoft/vscode-azurefunctions/pull/4906)] Refactor **cpUtils** to use `vscode-processutils`
+* [[4920](https://github.com/microsoft/vscode-azurefunctions/pull/4920)] Migrate tests to use testApi with esbuild
+* Bump 15 dependencies across build, test, and tooling infrastructure
 
 ## 1.20.3 - 2025-12-16