Refactor Stripe integration: single Connect webhook, account pages, cleanup

Stripe webhook:
- Single webhook endpoint /stripe/webhook for Connect + payment events
- v2 Connect events configured manually in Stripe Dashboard (not via API)
- account.updated syncs charges_enabled/payouts_enabled via API retrieve
- Remove StripeSyncCommand and saveWebhookSecret (secret managed via Ansible vault)

Account page (/mon-compte):
- Buyer tabs: Billets, Achats, Factures, Parametres
- Organizer tabs: Evenements/Brocantes, Sous-comptes, Virements + buyer tabs
- Stripe Connect status banner: setup required, pending verification, active, refused
- Stripe Connect onboarding: create account, complete verification (GET links)
- Dashboard Stripe: opens in new tab via createLoginLink (Express dashboard)
- Cancel/close Stripe account: deletes via API + resets local fields
- Stripe required message on events/subaccounts/payouts tabs when not active
- Settings: organizer fields locked (name, address), email/phone editable
- Return/refresh routes for Stripe Connect onboarding flow
- Error handling with flash messages on all Stripe operations
- Auto-sync Stripe status on /mon-compte visit

StripeService cleanup:
- Remove syncWebhook, saveWebhookSecret, getWebhookUrl, projectDir
- Add deleteAccount method
- Keep: verifyWebhookSignature, createAccountConnect, createAccountLink, createLoginLink

Security:
- Add connect.stripe.com and dashboard.stripe.com to nelmio whitelist
- Add STRIPE_SK, STRIPE_WEBHOOK_SECRET, OUTSIDE_URL to .env.test

Tests: 19 AccountControllerTest, 4 StripeWebhookControllerTest, 1 StripeServiceTest

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.env.test

@@ -6,3 +6,6 @@ MEILISEARCH_API_KEY=test
 SONARQUBE_URL=https://sn.esy-web.dev
 SONARQUBE_BADGE_TOKEN=test
 SONARQUBE_PROJECT_KEY=e-ticket
+STRIPE_SK=sk_test_fake
+STRIPE_WEBHOOK_SECRET=whsec_test
+OUTSIDE_URL=https://test.example.com