chore: curate 0.6.0 public release payload

[kwalus]

Summary

• promote the reviewed 0.6.0 public release payload from Canopy-Dev into the public Canopy repo
• include the refreshed public docs and Meshspaces onboarding while excluding internal dev-mirror, Copilot, release-process, publication, and local-only assets
• keep the promotion scoped to the curated allowlist generated from the tightened public-release exclusion rules

Test plan

• Generated the public candidate file set from the reviewed exclusion rules
• Spot-checked that internal scripts, release-process docs, publication artifacts, and local helper files were excluded
• Verified public-facing docs like README, SECURITY, QUICKSTART, MESHSPACES, AGENT_ONBOARDING, and MCP_QUICKSTART remain included
• Human review of the public PR diff before merge

[kwalus]

Superseded by #64. Closing this earlier public-release PR because it included demo/showcase asset classes that should not have been part of the first curated public payload.