docs: rework documentation

[alexdukeinvertase]

Summary

Docs IA and voice pass so the left-hand nav explains coverage first, then Install (pick your path), with Reference for lookup. Details below.

What changed

Path	What changed	Why
docs.json	Documentation tab order is now Introduction (Overview, Coverage) → Install → Integrations → Troubleshooting. Reference tab holds CLI/config. Sidebar no longer lists Why or Pattern C. Header “Get started” CTA removed; GitHub card kept. Redirects added for retired URLs.	People should learn from the left nav, then choose an install guide. Lookup stays out of that path. Old links still work.
docs/index.mdx	Cut the why essay, Codecov proof block, and “what you get” list. Page is now warning → Install cards → Explore → Help.	Overview should send you to the right page, not re-teach the product.
docs/coverage.mdx	New page covering what we measure, how the pipeline works, what the dedicated test app is (with examples), and this package’s harness numbers/images.	That material was split across /why and /pattern-c. One explanation page is easier to read and to link from install guides.
docs/why.mdx, docs/pattern-c.mdx	Deleted. Both redirect to /coverage.	Their content now lives on Coverage; leaving empty or partial pages would send people to the wrong place.
docs/app-developers.mdx	Voice/tone polish (“Pattern C” / “harness” → dedicated test app + Coverage links; numbered steps → plain headings). Absorbed the short e2e-timing flush sequence into the flush section.	Install recipe unchanged. Only real content move: timing no longer has its own page.
docs/library-maintainers.mdx	Voice/tone polish. “Pattern C” out. “Layer 1 / Layer 2” → measure / fail CI / upload. Install deferred to app-developers (no longer re-taught here).	Same maintainer guide; duplicate install steps removed, not the matcher/assert content.
docs/agents.mdx	Voice/tone polish. Title → “Coding agents”. Removed the long paste-ready install prompt; replaced with a one-liner to app-developers.md. Rules and exit codes kept.	That long prompt duplicated the install guide. Constraints stay here.
docs/integration/android.mdx	Voice/tone polish only. Title “Android”. “Runtime + CLI” → “Pull and report”. “Pattern C” → Coverage link.	No recipe removed; wording matches the rest of the site.
docs/integration/ios.mdx	Voice/tone polish. Static vs dynamic frameworks as its own section. Removed this repo’s CI matrix table from the page (it remains on CI with Appium).	iOS page keeps product setup; matrix wasn’t unique here.
docs/integration/js.mdx	Voice/tone polish, plus fuller in-page babel.config.js / nyc.config.js examples (workspace cwd/include). Nothing dropped from the recipe.	Same how-to; examples got more concrete, not shorter.
docs/integration/ci-appium.mdx	Voice/tone polish and a shorter write-up. Title → “CI with Appium”. Pitfalls kept (simulator, WDA, Metro reverse, .ec under buildDir, pins, Gemfile json).	Tightened prose; did not drop the CI failure notes.
docs/integration/codecov.mdx	New, short page: which report files to upload and how flags keep platforms separate. Links to Coverage for the harness example; does not reuse those images.	Upload/flags needed a home without repeating the Coverage explanation or its screenshots.
docs/integration/e2e-timing.mdx	Deleted as its own page; flush → pull → assert sequence moved into app-developers. Redirect in place.	Only standalone page we removed under Integrations; content wasn’t unique beyond the install guide.
docs/reference/cli.mdx, config.mdx, index.mdx	CLI and config moved out of the Documentation sidebar into the Reference tab, with fuller command/flag/key tables. Old /cli and /config redirect here.	Lookup docs belong under Reference so the Documentation tab stays about understanding and install.
docs/troubleshooting/empty-coverage.mdx	New: assert exit 2, empty JaCoCo, missing JS library, Expo CocoaPods reject, no hits on a framework/library, CI failing before pull.	Those fixes were scattered through integration pages; empty coverage needs one place to start.
CONTRIBUTING.md, AGENTS.md	Updated links to docs/coverage.mdx (and related paths).	Maintainer docs still pointed at pages we removed.

Test plan

Compare live docs (main / https://docs.page/invertase/react-native-coverage) to this PR.
Do not treat the Summary table as true until the end.

Primary bar: no important technical information is missing. Content may move pages, but every live fact that still matters must appear somewhere on the PR docs (or be an intentional, called-out drop).

A. INDEPENDENT COMPARISON (first)
1. Inventory live vs PR: every sidebar href, every docs/**/*.mdx path, redirects in docs.json.
2. Classify each path: unchanged | voice/tone only | restructured | new | deleted/redirected | moved.
3. For deleted/moved live pages (e.g. /why, /pattern-c, /cli, /config, /integration/e2e-timing): map each substantive claim to its PR location. Fail if a claim vanishes with no replacement.
4. For install + integration pages: spot-check that commands, order, and constraints match live (Expo vs RN CLI, flush → pull → report → assert, exit 2, New Arch, dedicated test app, Android .ec under buildDir, iOS helper / static vs dynamic, JS babel/nyc scope). OK if wording changed; not OK if a step or constraint disappeared.
5. Crawl PR links + redirects + .md URLs + llms.txt (200 / correct targets; hash links on hosted or branch preview). Old live URLs that should redirect must land on the right PR page/section.
6. Assets: every image on PR pages loads; if a live image moved, confirm it still appears where the explanation lives.

B. VOICE / IA
Overview, Coverage (vs live Why + Pattern C), App developers, Library maintainers, Agents, Integrations, CLI/config (live vs Reference), troubleshooting.
- Overview routes; doesn’t clone the README.
- Agents/maintainers don’t teach a different install than app-developers.

C. TABLE AUDIT (last)
For each Summary row: pass / fail / overstated against A–B. Quote mismatches.

Report: live↔PR matrix, missing-tech checklist (claim → PR location or “intentional drop”), links/assets, table-row verdicts.