chore(release): prepare v0.1.9

[yzs15]

Summary

• Bump all runtime, packaging, and extension version sources to 0.1.9.
• Update the Windows build instructions to use the released installer name.

Verification

• go vet ./...
• go test -race -short -count=1 ./...
• go test -race -count=1 -tags=integration ./test/integration/...
• go test -count=1 -tags=e2e ./test/e2e/windows
• xvfb-run --auto-servernum npm test (extensions/agentserver-app)
• make package