chore(release/v2-candidate): release 2.0.0-alpha.3 (#5233)

Co-authored-by: Sasha Sobran <asobran@google.com>

Author: Jacksunwei

.github/.release-please-manifest-v2.json

@@ -1,3 +1,3 @@
 {
-  ".": "2.0.0-alpha.2"
+  ".": "2.0.0-alpha.3"
 }

CHANGELOG-v2.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## [2.0.0-alpha.3](https://github.com/google/adk-python/compare/v2.0.0-alpha.2...v2.0.0-alpha.3) (2026-04-09)
+
+### Features
+
+* **Workflow Orchestration:** Added Workflow(BaseNode) graph orchestration implementation, support for lazy scan deduplication and resume for dynamic nodes, partial resume for nested workflows, and state/artifact delta bundling onto yielded events.
+* **CLI and Web UI:** Added support for Workflow graph visualization in web UI, improved graph readability with distinct icons and shapes, and active node rendering in event graph.
+* **Documentation:** Added reference documentation for development (skills like adk-style, adk-git, and observability architecture).
+
 ## [2.0.0-alpha.1](https://github.com/google/adk-python/compare/v2.0.0-alpha.0...v2.0.0-alpha.1) (2026-03-18)
 
 ### Features