[codex] Deploy md-docrs worker

[ThomAub]

Summary

• Configure the Cloudflare Worker for the md-docrs.workedonmymachine.com custom domain.
• Replace the placeholder KRATE_KV id with production and preview KV namespace ids.
• Rename the repo-local docs.rs CLI skill frontmatter to rust-docrs-cli.

Validation

• cargo test --workspace
• cargo check -p md-docrs-worker --target wasm32-unknown-unknown
• uv run --with PyYAML python /Users/thomas/.codex/skills/.system/skill-creator/scripts/quick_validate.py skills/rust-docrs-cli
• env -u CLOUDFLARE_API_KEY -u CLOUDFLARE_ACCOUNT_ID npx wrangler deploy --dry-run
• CLI parity checks for anyhow, anyhow::Error, tokio@1.52.1::sync::Mutex, and target-specific tokio::sync::Mutex
• Production smoke checks against https://md-docrs.workedonmymachine.com

Deployment

Deployed md-docrs-worker to Cloudflare Workers with version id 84c8dccb-bb67-4c76-aedc-32e0d32e3744. Valid Worker responses returned 200 with text/markdown; charset=utf-8; invalid specs returned 400; missing items returned 404; /kv showed active cache keys.