Admin UX overhaul: P0 fixes, error-UX foundations, nav cleanup, tenant detail page

From the 2026-07-14 UI/UX audit (17/40). Four phases:

P1 — Settings route crashed on Agents→Edit (Input/Textarea used but never
imported). Added imports + a shared route-level error boundary
(components/route-error.tsx) re-exported from all shell routes, so one
crashing panel degrades to an explained card with the nav intact instead of
replacing the whole app with a stack trace. Corrected the stale CLAUDE.md
claim that `npm run typecheck` crashes — it works, and would have caught the
missing import.

P2 — Error/empty/feedback foundations. Fixed useSession identity churn that
fired ~3x duplicate fetches per screen and self-inflicted 429s (referentially
stable snapshot). New lib/errors.ts (describeError → plain-language + the fix)
and components/data-state.tsx (DataState renders exactly one of
error/loading/empty/content, so a failed load never shows as "empty";
DialogError for in-dialog failures; 429 auto-retry). Rolled across all 15
list routes; every mutation now toasts. Surfaced+fixed two silent-failure
bugs (sso + buckets-CORS swallowed load errors; the latter could wipe rules
on save).

P3 — Nav IA + trust cleanup. Default-expanded rail; regrouped into 7 coherent
sections; collapsed the Apps/Plan/Entitlements stub triplication into one
honest /billing page; deleted fabricated seeded notifications and the dead
Help menu item; fixed the 403 copy (referenced a tenant switcher that doesn't
exist); removed orphan /assistant + /library routes; gated dev-seed login
hints behind DEV; renamed /activity → /audit-log with a redirect.

P4 — Tenant detail page (routes/tenants.$id.tsx + components/tenant-detail/*),
closing the provision→configure gap. 8 tabs (Overview, Plan & quotas,
Branding, Localization, Email & SMS, Feature flags, IP rules, Inbound
webhooks), each verified saving to the real backend. Row name links to detail.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CLAUDE.md

@@ -26,7 +26,7 @@ This file is a quick map, not a duplication of upstream docs.
 - `npm run dev` — Vite dev server (React Router 7).
 - `npm run build` — production build (`react-router build`).
 - `npm run start` — serve the built app (`react-router-serve ./build/server/index.js`).
-- `npm run typecheck` — `react-router typegen && tsc`. See gotcha below; may crash.
+- `npm run typecheck` — `react-router typegen && tsc`. **Works** (2026-07-14). Run it before every commit.
 - `start.sh` / `stop.sh` — repo's preferred way to run/stop the dev server in the background.
 
 - `npm run test` — Vitest run (vibespace-inherited setup; jsdom + @testing-library/react).
@@ -141,6 +141,7 @@ This repo was scaffolded from `create-crema-app`, which patches marker comments.
 
 ## Known gotchas
 
-- `npm run typecheck` may crash with a TypeScript internal error — pre-existing in the Crema toolchain. There's no test runner here, so rely on careful reads + dev server.
+- `npm run typecheck` **does not crash** — verified 2026-07-14. The old "it crashes, rely on careful reads" note was stale, and it cost us: a route shipped using `Input`/`Textarea` without importing them, which `tsc` reports instantly as TS2304 but nobody was running it. It currently reports ~39 pre-existing errors in `app/` (mostly `TS2322` prop mismatches) and more in sibling libs; treat *new* errors as blocking even while that backlog stands.
+- Every route that renders `<AppShell>` re-exports a shared route-level error boundary (`app/components/route-error.tsx`). Keep that export when adding routes — without it, one crashing panel replaces the entire console with an unstyled stack trace and strands the operator with no nav.
 - Vite "Outdated Optimize Dep" 504s after editing `vite.config.ts` or `tsconfig.json`: stop dev, `rm -rf node_modules/.vite`, restart, hard-reload.
 - After editing a sibling lib's exports, the dev server sometimes needs a manual restart to pick up the new types.