Prepare Agentflow v0.0.5 release

[saintdle]

Summary

• Set the package and runtime version to 0.0.5.
• Publish the controller-routing and context-reliability changes under a dated changelog section.
• Align CI distribution assertions, installation instructions, migration examples, and current-version documentation.

Validation

• 504 tests passed; 1 skipped.
• Repository validation passed.
• Version 0.0.5 wheel and source distribution built successfully.
• Distribution contents and privacy boundary passed inspection.
• Clean-wheel installation and CLI smoke tests passed.
• Git diff validation passed.

Release plan

After this PR and the resulting main-branch CI, security, and CLI-build workflows pass, tag the reviewed merge commit as v0.0.5. The tag workflow will build immutable artifacts and publish a GitHub prerelease.