docs: relaunch homepage with determinism-led narrative and precision design

[swernerx]

What changed

Complete rebuild of the docs homepage — new narrative, new copy, new visual system, and an interactive centerpiece.

Narrative (7 blocks): Hero leads with the ownable claim — "It's just ESLint. Resolved ahead of time. Accelerated by Rust." — followed by an interactive flag configurator, the determinism argument (before/after), the OxLint split, AI guardrails, a linked "receipts" section replacing the logo wall a v0.5 project can't have, and a closing that mirrors the hero. All eight previous sections were replaced.

Flag configurator: Four toggles (react/node/ai/oxlint) live-update the two-line config, the active rule count, the resolved hash filename, and (with oxlint on) the Rust/ESLint split bar. The numbers are generated at build time by docs/scripts/generate-config-stats.ts, which reuses the package's own composeConfig/hash/codegen logic — so everything shown is true by construction and drifts visibly in PR diffs (docs/app/generated/config-stats.json is committed and regenerated on every build).

Visual system: Monochrome OKLCH ramp + one signal-green accent (hue 155). The --ardo-hue-brand override recolors the doc shell too, fixing the previous teal-homepage/red-shell mismatch. Fonts are now self-hosted via Fontsource (Schibsted Grotesk, Fragment Mono, JetBrains Mono) — the render-blocking Google Fonts @import is gone. No gradient text, no glow backgrounds, no section eyebrows/numbered markers, restrained state-driven motion with a full prefers-reduced-motion block.

Package change: one-word export of resolveRulesForFile in packages/eslint-config/src/build/codegen.ts so the stats script resolves rules exactly like the generator.

Why

The previous homepage leaned on generic SaaS-template patterns (gradient headline, teal/violet glows, identical card grids) and qualitative claims. The relaunch positions the project on what competitors can't copy — pre-generated deterministic configs plus the automated ESLint/OxLint split — and backs every number with a linked artifact (tests, snapshot, ADRs, CI matrix).

Notes for review

• Verified: pnpm run lint (self + docs, 0 errors), 202 package tests green, docs:build prerender succeeds with real rule counts in the HTML, configurator/dark mode/mobile checked in the browser.
• Receipts state 202 tests (the 170 in older docs material was stale) and exact per-permutation rule counts (575 base / 698 react / 771 react+ai / 785 all) counted with the generator's own resolution logic.
• The green hue recolors all doc pages via the Ardo token — worth a quick visual pass on a few guide/ADR pages.
• docs/PRODUCT.md + docs/DESIGN.md added as durable design context; .claude/launch.json added for browser preview during development.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.42%. Comparing base (8f193a2) to head (1337928).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #97   +/-   ##
=======================================
  Coverage   89.42%   89.42%           
=======================================
  Files          39       39           
  Lines         889      889           
  Branches      182      182           
=======================================
  Hits          795      795           
  Misses         79       79           
  Partials       15       15           

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[greptile-apps]

Greptile Summary

This PR rebuilds the docs homepage around generated config data and a new visual system. The main changes are:

• New homepage sections and interactive flag configurator.
• Build-time generation of committed config statistics.
• Self-hosted font imports and rewritten homepage CSS.
• Product and design notes for the docs site.
• A small export change in the config codegen helper.

Confidence Score: 4/5

The docs build path needs a dependency-boundary fix before merging.

• The homepage configurator data maps cleanly across all flag combinations.
• The new docs data script reaches into package source during the docs build.
• A docs-only install can miss package source-time dependencies and fail before prerendering.

docs/scripts/generate-config-stats.ts and docs/package.json

Important Files Changed

Filename	Overview
docs/scripts/generate-config-stats.ts	Adds the docs data generator that imports package source and writes homepage config stats.
docs/app/lib/configStats.ts	Adds typed accessors for generated config stats and mirrors the package bitmask order.
docs/app/components/home/FlagConfigurator.tsx	Adds the interactive flag selector for the generated homepage data.
docs/app/components/home/configuratorData.ts	Adds flag metadata, shared links, and generated config snippet text.
docs/app/routes/home.tsx	Replaces the old homepage composition with the new narrative sections.
docs/app/root.tsx	Adds self-hosted Fontsource CSS imports before homepage styling.
docs/package.json	Runs generated data before docs dev/build and adds new docs-only development dependencies.
packages/eslint-config/src/build/codegen.ts	Exports an existing rule-resolution helper without changing its implementation.

_{Reviews (1): Last reviewed commit: "docs: relaunch homepage with determinism..." | Re-trigger Greptile}