2026.6.6

Changes

• Bumped release versions to 2026.6.6 for adk_dart, adk, adk_mcp, and flutter_adk.
• Updated the exported ADK runtime baseline to 2.2.0 to match the current adk-python reference baseline.
• Added broad workflow parity coverage, including workflow nodes, routed edges, dynamic run IDs, request-input helpers, retry/cancellation/concurrency handling, replay/resume/rehydration, nested workflow events, graph serialization, and status-aware graph DOT output.
• Expanded runtime event and conversion parity with structured events, node path building, A2A metadata preservation, Event routing helpers, and output-key callback visibility coverage.
• Added newer integration/tool surfaces, including GCP Skill Registry, BigQuery integration exports, environment tools, public skill tools, URL/load-web-page handling, Vertex RAG retrieval updates, and OpenAI labs adapter support.
• Hardened model, streaming, and tool-call behavior across Gemini schemas, Anthropic/LiteLLM/Apigee paths, REST streaming function continuations, streaming tool-call preservation, and cooperative abort handling.
• Updated adk_mcp non-IO stdio stub parity and hardened cancellation coverage.
• Refreshed flutter_adk example/documentation surface and consolidated repository documentation under docs/knowledge and docs/worklog.

Verification

• dart test passed: 1326 passed, 3 skipped.
• dart analyze lib test passed with existing info-level lint noise only.
• dart analyze / dart test passed for packages/adk.
• dart analyze / dart test passed for packages/adk_mcp.
• flutter analyze / flutter test passed for packages/flutter_adk.
• flutter pub get passed for packages/flutter_adk/example.