[codex] Add launch awareness assets

[spaceshipmike]

Summary

• add lightweight launch/awareness draft assets grounded in the README proof
• include positioning, repo description, LinkedIn/Reddit/direct-outreach drafts, and a single-page marketing-site outline
• update the public-readiness plan while keeping real alpha MCP-control feedback pending

Checks

• git diff --check
• git diff --cached --check
• worker review ran git diff --check and inspected doc links

Skipped verification

• Build/test not run because this is docs-only.