feat(billing): paywall conversion pass (deferred first charge, trial touchpoint, sell-view upgrade) (#991)

* feat(billing): paywall conversion pass: deferred first charge, trial touchpoint, sell-view upgrade

- checkout passes subscription_data.trial_end (trial grant expiry, 49h floor)
  so a mid-trial upgrade costs 0 kr today instead of double-billing days the
  company already has free; billing/status counts 'trialing' as paying
- trial countdown pill in the sidebar (CompanyContext.trialEndsAt via
  getCompanyEntitlements); hidden for sandbox, dev bypass, and once any
  non-trial grant is active
- sell view: what-happens-when timeline, free-vs-paid comparison table,
  risk-reversal copy + chevron CTA, post-checkout confirmation state

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

* fix(billing): review triage: fail-closed trial lookup, hourly countdown refresh, BFL retention note

- checkout returns 500 (no Stripe session) when the trial-grant lookup errors,
  instead of silently charging immediately after the UI promised 0 kr idag
- sidebar trial countdown recomputes hourly so a long-lived tab stays honest
- sell-view retention copy states BFL 7-year retention explicitly
  (compliance-bot suggestion)

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

* chore: retrigger CI (pull_request event delivery stuck)

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

app/api/billing/status/route.ts

@@ -37,9 +37,12 @@ export async function GET() {
       .eq('company_id', companyId)
       .maybeSingle()
     const status = (sub as { status: string | null } | null)?.status ?? null
-    // Paying = a real subscription. Deliberately excludes 'trialing' so a
-    // trialing company still sees the upgrade path (not the manage button).
-    isPaying = status === 'active' || status === 'past_due'
+    // Paying = a real subscription. Includes 'trialing': checkout defers the
+    // first charge to the product-trial end, so a Stripe-trialing subscription
+    // means the card is already committed and the user should see the manage
+    // view, not the upgrade pitch. Companies without a subscription (product
+    // trial only, no card) stay on the upgrade path.
+    isPaying = status === 'active' || status === 'past_due' || status === 'trialing'
 
     const { data: trial } = await supabase
       .from('capability_grants')