feat: add get_min_product_discount and llm_id_to_product_id

- get_min_product_discount: find minimum discount for a product across all
  active discount records (customer-specific + NULL + '*' fallback)
- llm_id_to_product_id: convert llmage.llm.id to sage.product.id
- Both registered in load_discount() for use in pricing display

discount/init.py

@@ -276,6 +276,90 @@ where discountid = ${discountid}$
     return 1.0
 
 
+async def sor_get_min_product_discount(sor, product_id, resellerid, customerid):
+    """Find the minimum discount for a specific product from active discount records.
+
+    Searches all active discount records for the given (resellerid, customerid),
+    including fallback to customerid=NULL and customerid='*' defaults.
+    Returns the minimum discount value across all matching discount_detail rows.
+
+    Args:
+        sor: sqlor context
+        product_id: product.id
+        resellerid: LLM owner's org id (discount.resellerid)
+        customerid: user's org id (discount.customerid)
+
+    Returns: minimum discount value (float), 1.0 if no discount found.
+    """
+    env = ServerEnv()
+    biz_date = await env.get_business_date(sor)
+
+    sql = """SELECT dd.discount
+FROM discount_detail dd
+JOIN discount d ON dd.discountid = d.id
+WHERE d.resellerid = ${resellerid}$
+    AND (d.customerid = ${customerid}$ OR d.customerid IS NULL OR d.customerid = '*')
+    AND d.enabled_date <= ${biz_date}$
+    AND d.expired_date > ${biz_date}$
+    AND dd.productid = ${product_id}$"""
+    ns = {
+        'resellerid': resellerid,
+        'customerid': customerid,
+        'biz_date': biz_date,
+        'product_id': product_id,
+    }
+    recs = await sor.sqlExe(sql, ns)
+
+    if recs:
+        discounts = [r.discount for r in recs if r.discount is not None]
+        if discounts:
+            return min(discounts)
+
+    return 1.0
+
+
+async def get_min_product_discount(product_id, resellerid, customerid):
+    """Get the minimum discount for a specific product (convenience wrapper).
+
+    Args:
+        product_id: product.id
+        resellerid: LLM owner's org id
+        customerid: user's org id
+
+    Returns: minimum discount value (float), 1.0 if no discount found.
+    """
+    env = ServerEnv()
+    dbname = env.get_module_dbname('discount')
+    config = getConfig()
+    db = DBPools()
+    db.databases = config.databases
+    async with db.sqlorContext(dbname) as sor:
+        return await sor_get_min_product_discount(sor, product_id, resellerid, customerid)
+    return 1.0
+
+
+async def llm_id_to_product_id(llm_id):
+    """Convert an LLM model ID (llmage.llm.id) to a product ID (sage.product.id).
+
+    Args:
+        llm_id: llmage.llm.id
+
+    Returns: product.id or None if not found.
+    """
+    env = ServerEnv()
+    dbname = env.get_module_dbname('discount')
+    config = getConfig()
+    db = DBPools()
+    db.databases = config.databases
+    async with db.sqlorContext(dbname) as sor:
+        sql = """SELECT id FROM product
+WHERE resource_ref_id = ${llm_id}$ AND product_type = 'llm_model' LIMIT 1"""
+        recs = await sor.sqlExe(sql, {'llm_id': llm_id})
+        if recs:
+            return recs[0].id
+        return None
+
+
 async def get_customer_discount(resellerid, customerid):
     """Legacy: get default discount for a customer (all products)."""
     env = ServerEnv()
@@ -770,6 +854,9 @@ def load_discount():
     env.sor_get_customer_discount = sor_get_customer_discount
     env.get_product_discount = get_product_discount
     env.sor_get_product_discount = sor_get_product_discount
+    env.sor_get_min_product_discount = sor_get_min_product_discount
+    env.get_min_product_discount = get_min_product_discount
+    env.llm_id_to_product_id = llm_id_to_product_id
     env.discount_qrcode = discount_qrcode
     env.set_promote_discount = set_promote_discount
     env.get_discount_details = get_discount_details