Python: Bump agent-framework-devui to 1.0.0b260414 for release (#5259)

Update devui version and changelog for the streaming memory fix release.

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

Author: giles17

python/CHANGELOG.md

@@ -10,6 +10,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - **agent-framework-azure-cosmos**: [BREAKING] `CosmosCheckpointStorage` now uses restricted pickle deserialization by default, matching `FileCheckpointStorage` behavior. If your checkpoints contain application-defined types, pass them via `allowed_checkpoint_types=["my_app.models:MyState"]`. ([#5200](https://github.com/microsoft/agent-framework/issues/5200))
 
+## [devui-1.0.0b260414] - 2026-04-14
+
+### Fixed
+- **agent-framework-devui**: Fix streaming memory growth in DevUI frontend ([#5221](https://github.com/microsoft/agent-framework/pull/5221))
+
 ## [1.0.1] - 2026-04-09
 
 ### Added

python/packages/devui/pyproject.toml

@@ -4,7 +4,7 @@ description = "Debug UI for Microsoft Agent Framework with OpenAI-compatible API
 authors = [{ name = "Microsoft", email = "af-support@microsoft.com"}]
 readme = "README.md"
 requires-python = ">=3.10"
-version = "1.0.0b260409"
+version = "1.0.0b260414"
 license-files = ["LICENSE"]
 urls.homepage = "https://github.com/microsoft/agent-framework"
 urls.source = "https://github.com/microsoft/agent-framework/tree/main/python"