Adopt the Fleet code health standard

[sarthakagrawal927]

Adopt the Fleet code-health contract across the root docs tooling, dashboard app, public landing, and RAG Worker.

Scope:

• expose repository-native checks for format, lint, types, tests, unused code, complexity, duplication, coverage, dependency risk, cycles, suppressions, and repository hygiene
• remove only high-confidence dead code or dependencies
• measure legacy debt and enforce exact no-regression ratchets
• keep generated, fixture, migration, and retired-reference boundaries explicit
• link remaining debt to a dated follow-up issue

No deploy, migration, production configuration, or behavior change is part of this work.