✨ feat(server): /api/info aggregator + frontend version footer

Sprint 2 of autonomous trainer day 2026-05-05. Mistral-implemented
through ICM workspace ship-info-aggregator (bootstrapped backend +
BDD before hitting price limit at stage 02), Claude-completed for
frontend + Playwright + verifier + PR.

Backend:
- GET /api/info aggregator returning version, commit_short, build_date,
  uptime_seconds, cache_enabled, healthz_status (single round trip)
- Optional cache via existing cache service (X-Cache: HIT/MISS)
- BDD scenario @critical covers happy path + version regex; cache
  scenario kept under @skip @bdd-deferred until BDD harness gains a
  cache-enabled mode

Frontend:
- AppFooterView (dumb) + AppFooter (smart wrapper, useFetch) following
  the HealthDashboard / HealthDashboardView pattern
- layouts/default.vue auto-applied via NuxtLayout in app.vue
- humaniseUptime helper in utils/
- Playwright tests use route.fulfill mocking (decoupled from dev-proxy
  infra), assert visible AND content (PR #32 lesson)

Docs:
- documentation/API.md /api/info entry with schema and rationale
- ADR-0026 documents composite endpoint vs separate calls choice

Verifier verdict (skill-driven, audit at stage 04): APPROVE_WITH_NITS.
Nits: handleInfo is 51 lines (could split into builder + emitter);
X-Cache: DISABLED could improve ops clarity.

Out-of-scope follow-up: existing tests/e2e/health.spec.ts happy path
hits the same dev-proxy infra issue as my footer happy path before
mocking. Same fix (server: false + route.fulfill) would apply.

frontend/components/AppFooter.vue

@@ -0,0 +1,13 @@
+<script setup lang="ts">
+import AppFooterView, { type AppInfo } from './AppFooterView.vue'
+
+// Wrapper: handles data fetching, delegates rendering to AppFooterView.
+// Separation of concerns (SRP) - same pattern as HealthDashboard / HealthDashboardView.
+// server: false → fetch client-side only. Avoids SSR fetching through the dev proxy
+// (which can fail in some local setups), and lets Playwright route mocks apply.
+const { data, pending, error } = useFetch<AppInfo>('/api/info', { server: false })
+</script>
+
+<template>
+  <AppFooterView :data="data" :pending="pending" :error="error" />
+</template>