Adopt the Fleet code-health quality gate

[sarthakagrawal927]

Adopt the Fleet-wide measurable code-health standard in RolePatch. Scope: root app, Chrome extension, Astro landing overlay, and CI. Add regression-only checks for native formatting/lint/type/test/build, coverage, unused code/packages, complexity, duplication, import cycles, dependency advisories, suppressions, and repository hygiene. Preserve runtime behavior and existing active work. This issue tracks the independently shippable adoption PR.

[sarthakagrawal927]

Final acceptance evidence: draft PR #51 is green on cb51667. Hosted CI https://github.com/Significant-Hobbies/rolepatch/actions/runs/31568802698 passed pnpm quality and pnpm cf:build in 3m6s; all five PR checks pass. The gate covers the Next app, Worker, extension, Astro overlay, scripts, docs, and production build. Reviewed metrics receipt: run_c87927dc5df18771c1d44a8178332286; generic cleanup evidence: run_86a8699aa08392f596c40b3426c99d26.