All ~165 legacy var() usages (--color-*, --surface*, --accent*, --border,
--text*) with hex fallbacks and ~150 raw hex literals across app.scss and
24 scoped style blocks are swapped to the kit's --gn-* tokens per the
intent of the old fallback values:

- accent/primary/teal (#7aa2f7/#4ec9b0) -> --gn-color-secondary
- amber/orange highlights -> --gn-color-accent
- text greys -> --gn-color-text-{light,medium,dark}
- panels -> --gn-surface-panel; elevated tints -> color-mix over panel
- translucent overlays -> color-mix(in srgb, ..., transparent)

Deliberately literal: terminal deep bg #0f0f14 (darker than any token)
and the content-card image badge teal #89dceb (kit has no teal). File
type badges keep a categorical palette via nearest kit tokens.

Dead "UI kit overrides" block halved: kit 1.0 dropped hover icon
rotation, so only the app-owned chevron open-state flip remains.

Verified: vitest 111 passed, build OK, dev render matches W1 baseline

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Backend:
- navi/auth/deps.py: replace 3 DB round-trips with single JOIN query for
  token resolution; update last_used_at still separate (best-effort)
- navi/api/routes/api_tokens.py: replace asyncpg-specific "UPDATE 1"
  string check with RETURNING id fetchrow; increase token_prefix from
  8 to 12 chars for better visual identification; add security notes
- tests/unit/auth/test_api_tokens.py: update tests for JOIN query and
  RETURNING-based revoke

Frontend:
- webclient/src/components/settings/ShowTokenModal.vue: new modal that
  shows the plain token in a readonly field with copy button and
  explicit warning — replaces the transient toast notification
- webclient/src/components/settings/ApiKeysPanel.vue: use ShowTokenModal
- webclient/src/composables/useWebSocket.js: add security comment about
  localStorage XSS risk and query param log exposure

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>