Playground UX & Security Docs

This release improves the dashboard playground experience and expands Daytona’s documentation. The playground now keeps preview URLs valid longer and returns screenshots as downloadable files instead of raw base64 strings, with minor code block styling refinements.

A new security exhibit has been added to the docs, providing a formal security disclosure document for compliance and trust purposes. On the infrastructure side, a Redis cache race condition in the proxy and otel-collector has been fixed by eliminating redundant Has/Get calls, and the runner daemon no longer cancels telemetry initialization prematurely.

Additional chores include pinning rubocop to v1.84.2, adding git to dependent Dockerfiles, and bumping the Go SDK to v0.147.0.