docs: publish v1.7.0 homepage

[nugehs]

Summary

• update the public docs homepage from v1.6.2 to the verified v1.7.0 release
• feature the gate-effectiveness corpus and direct npm, GitHub Release, and MCP Registry links
• make the published npm package the default install path
• remove the unsupported material-sparkles token visible in the rendered heading

Validation

• mkdocs build --strict
• npm run ci
• Otito staged gate with exact-tree validation: PASS
• desktop and 390 px browser review; no raw material token or mobile overflow

Public release proof

• npm latest: 1.7.0
• GitHub Release v1.7.0 published
• MCP Registry io.github.BASHBOP/otito latest: 1.7.0