feat(billing): A6 — planner/supplier routes use get_price_id() + _provider()

- planner/routes.py: import get_price_id instead of get_paddle_price,
  export_checkout uses _provider().build_checkout_payload()
- suppliers/routes.py: all get_paddle_price → get_price_id,
  signup_checkout uses _provider().build_multi_item_checkout_payload(),
  dashboard boosts use get_all_price_ids() bulk load

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

web/src/padelnomics/planner/routes.py

@@ -18,7 +18,7 @@ from ..core import (
     feature_gate,
     fetch_all,
     fetch_one,
-    get_paddle_price,
+    get_price_id,
     utcnow_iso,
 )
 from ..i18n import get_translations
@@ -687,7 +687,9 @@ async def export_details():
 @login_required
 @csrf_protect
 async def export_checkout():
-    """Return JSON for Paddle.js overlay checkout for business plan PDF."""
+    """Return checkout JSON for business plan PDF (works with Paddle overlay or Stripe redirect)."""
+    from ..billing.routes import _provider
+
     form = await request.form
     scenario_id = form.get("scenario_id")
     language = form.get("language", "en")
@@ -703,23 +705,20 @@ async def export_checkout():
     if not scenario:
         return jsonify({"error": "Scenario not found."}), 404
 
-    price_id = await get_paddle_price("business_plan")
+    price_id = await get_price_id("business_plan")
     if not price_id:
         return jsonify({"error": "Product not configured. Contact support."}), 500
 
-    return jsonify(
+    payload = _provider().build_checkout_payload(
-        {
+        price_id=price_id,
-            "items": [{"priceId": price_id, "quantity": 1}],
+        custom_data={
-            "customData": {
+            "user_id": str(g.user["id"]),
-                "user_id": str(g.user["id"]),
+            "scenario_id": str(scenario_id),
-                "scenario_id": str(scenario_id),
+            "language": language,
-                "language": language,
+        },
-            },
+        success_url=f"{config.BASE_URL}/planner/export/success",
-            "settings": {
-                "successUrl": f"{config.BASE_URL}/planner/export/success",
-            },
-        }
     )
+    return jsonify(payload)
 
 
 @bp.route("/export/success")

web/src/padelnomics/suppliers/routes.py

@@ -17,7 +17,8 @@ from ..core import (
     feature_gate,
     fetch_all,
     fetch_one,
-    get_paddle_price,
+    get_all_price_ids,
+    get_price_id,
     is_flag_enabled,
 )
 from ..i18n import get_translations
@@ -383,7 +384,9 @@ def _compute_order(data: dict, included_boosts: list, t: dict) -> dict:
 @bp.route("/signup/checkout", methods=["POST"])
 @csrf_protect
 async def signup_checkout():
-    """Validate form, return JSON for Paddle.js overlay checkout."""
+    """Validate form, return checkout JSON (Paddle overlay or Stripe redirect)."""
+    from ..billing.routes import _provider
+
     form = await request.form
     accumulated = _parse_accumulated(form)
 
@@ -401,9 +404,9 @@ async def signup_checkout():
         if period == "yearly"
         else plan_info.get("paddle_key_monthly", plan)
     )
-    plan_price_id = await get_paddle_price(price_key)
+    plan_price_id = await get_price_id(price_key)
     if not plan_price_id:
-        return jsonify({"error": "Invalid plan selected. Run setup_paddle first."}), 400
+        return jsonify({"error": "Invalid plan selected. Run setup first."}), 400
 
     # Build items list
     items = [{"priceId": plan_price_id, "quantity": 1}]
@@ -416,14 +419,14 @@ async def signup_checkout():
 
     for b in BOOST_OPTIONS:
         if b["type"] in selected_boosts and b["type"] not in included_boosts:
-            price_id = await get_paddle_price(b["key"])
+            price_id = await get_price_id(b["key"])
             if price_id:
                 items.append({"priceId": price_id, "quantity": 1})
 
     # Add credit pack (one-time)
     credit_pack = accumulated.get("credit_pack", "")
     if credit_pack:
-        price_id = await get_paddle_price(credit_pack)
+        price_id = await get_price_id(credit_pack)
         if price_id:
             items.append({"priceId": price_id, "quantity": 1})
 
@@ -477,15 +480,12 @@ async def signup_checkout():
         "plan": plan,
     }
 
-    return jsonify(
+    payload = _provider().build_multi_item_checkout_payload(
-        {
+        items=items,
-            "items": items,
+        custom_data=custom_data,
-            "customData": custom_data,
+        success_url=f"{config.BASE_URL}/suppliers/signup/success",
-            "settings": {
-                "successUrl": f"{config.BASE_URL}/suppliers/signup/success",
-            },
-        }
     )
+    return jsonify(payload)
 
 
 @bp.route("/claim/<slug>")
@@ -1035,12 +1035,8 @@ async def dashboard_boosts():
         (supplier["id"],),
     )
 
-    # Resolve Paddle price IDs for buy buttons
+    # Resolve price IDs for buy buttons (from active provider)
-    price_ids = {}
+    price_ids = await get_all_price_ids()
-    for b in BOOST_OPTIONS:
-        price_ids[b["key"]] = await get_paddle_price(b["key"])
-    for cp in CREDIT_PACK_OPTIONS:
-        price_ids[cp["key"]] = await get_paddle_price(cp["key"])
 
     return await render_template(
         "suppliers/partials/dashboard_boosts.html",