Naragate v0.5.1 — Auto-renew Sectors account tokens

Sectors account tokens renew automatically

The Usage page's authoritative account block no longer depends on a manually
captured OAuth token.

What changed

• Auto-renewal uses the dashboard's own login: POST /auth/token/ with
  email + password returns {refresh, access} — no OAuth client_id
  needed (that was the earlier blocker). Email/password renewal is tried
  first; the OAuth refresh grant remains as a fallback.
• SECTORS_ACCOUNT_EMAIL / SECTORS_ACCOUNT_PASSWORD are passed through
  compose; tokens resolve runtime-settings-first, then env.
• The manual "paste tokens" modal was dropped — unnecessary now.

Configure

SECTORS_ACCOUNT_EMAIL=you@example.com
SECTORS_ACCOUNT_PASSWORD=…

With these set, the account card self-heals when the access token expires.
Endpoint and rationale documented in references/sectors-account-usage.md.

Backend 406 tests, frontend production build — green. (naragate-mcp unchanged.)