chore: remove dead Supabase/Stripe env vars from docker-compose and env example

Frontend build args and runtime env no longer need NEXT_PUBLIC_SUPABASE_URL,
NEXT_PUBLIC_SUPABASE_ANON_KEY, SUPABASE_SERVICE_ROLE_KEY, STRIPE_SECRET_KEY,
STRIPE_WEBHOOK_SECRET — all replaced by V2 gateway. .env.v2.example updated to
reflect the current V2-only config.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.env.v2.example

@@ -26,6 +26,12 @@ CORS_ORIGIN=http://localhost:3000
 # The only backend port exposed to the host. Change if 8080 is taken locally.
 GATEWAY_PORT=8080
 
+# ── Frontend public vars (baked into the Next.js image at build time) ────────
+NEXT_PUBLIC_SITE_URL=http://localhost:3000
+# Browser-facing gateway URL (host port). Must match GATEWAY_PORT above.
+NEXT_PUBLIC_API_URL=http://localhost:8080/v1
+NEXT_PUBLIC_TENANT_SLUG=flatrender
+
 # ── ZarinPal (Iranian payment gateway) ───────────────────────────────────────
 # Get your merchant ID from https://www.zarinpal.com/
 ZARINPAL_MERCHANT_ID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
@@ -49,12 +55,4 @@ TARA_CALLBACK_URL=https://yourdomain.com/v1/payments/callback/tara
 # ── Stripe (international payment gateway) ───────────────────────────────────
 # Get keys from https://dashboard.stripe.com/apikeys
 STRIPE_SECRET_KEY=sk_test_...
-STRIPE_WEBHOOK_SECRET=whsec_...
 STRIPE_PUBLISHABLE_KEY=pk_test_...
-
-# ── Next.js frontend (NEXT_PUBLIC_* baked at build time) ─────────────────────
-NEXT_PUBLIC_SUPABASE_URL=https://your-project.supabase.co
-NEXT_PUBLIC_SUPABASE_ANON_KEY=eyJ...
-NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY=pk_test_...
-NEXT_PUBLIC_SITE_URL=http://localhost:3000
-SUPABASE_SERVICE_ROLE_KEY=eyJ...

docker-compose.v2.yml

@@ -272,13 +272,10 @@ services:
     build:
       context: .
       args:
-        NEXT_PUBLIC_SUPABASE_URL:            "${NEXT_PUBLIC_SUPABASE_URL:-}"
-        NEXT_PUBLIC_SUPABASE_ANON_KEY:       "${NEXT_PUBLIC_SUPABASE_ANON_KEY:-}"
-        NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY:  "${NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY:-}"
-        NEXT_PUBLIC_SITE_URL:                "${NEXT_PUBLIC_SITE_URL:-http://localhost:3000}"
+        NEXT_PUBLIC_SITE_URL:     "${NEXT_PUBLIC_SITE_URL:-http://localhost:3000}"
         # V2 gateway: browser-facing base (host port) baked in at build time.
-        NEXT_PUBLIC_API_URL:                 "${NEXT_PUBLIC_API_URL:-http://localhost:${GATEWAY_PORT:-8088}/v1}"
-        NEXT_PUBLIC_TENANT_SLUG:             "${NEXT_PUBLIC_TENANT_SLUG:-flatrender}"
+        NEXT_PUBLIC_API_URL:      "${NEXT_PUBLIC_API_URL:-http://localhost:${GATEWAY_PORT:-8080}/v1}"
+        NEXT_PUBLIC_TENANT_SLUG:  "${NEXT_PUBLIC_TENANT_SLUG:-flatrender}"
     container_name: fr2-frontend
     restart: unless-stopped
     ports:
@@ -289,10 +286,6 @@ services:
       HOSTNAME: "0.0.0.0"
       # Server-side: Next route handlers reach the gateway over the internal network.
       API_GATEWAY_URL: "http://gateway:8080"
-      # Server-side secrets (not baked into image)
-      SUPABASE_SERVICE_ROLE_KEY:  "${SUPABASE_SERVICE_ROLE_KEY:-}"
-      STRIPE_SECRET_KEY:          "${STRIPE_SECRET_KEY:-}"
-      STRIPE_WEBHOOK_SECRET:      "${STRIPE_WEBHOOK_SECRET:-}"
     depends_on:
       gateway:
         condition: service_healthy