variants/novacustom_nv4x_adl/releases_heads.md: add proper introduction and newsletter button

Signed-off-by: Filip Lewiński <[email protected]>

Author: filipleple

docs/variants/novacustom_nv4x_adl/releases_heads.md

@@ -1,8 +1,24 @@
 # NovaCustom NV4x 12th Gen Dasharo (coreboot + heads) Release Notes
 
+This is a Dasharo Pro Package Release. To access the pre-built binaries,
+you need to [subscribe to the Dasharo Pro Package subscriber](https://docs.dasharo.com/ways-you-can-help-us/#become-a-dasharo-pro-package-subscriber).
+You can do this by purchasing a Dasharo Pro Package product from our [shop](https://shop.3mdeb.com/shop/dasharo-pro-package/1-year-dasharo-entry-subscription-for-network-appliance/).
+
+As a subscriber, you will receive access to all firmware updates for the
+duration of your subscription via the Dasharo Pro Package newsletter,
+and gain entry to the Dasharo Premier Support invite-only live chat on
+the Matrix network, enabling direct engagement with the Dasharo Team and fellow
+subscribers for personalized, priority assistance.
+
 Following Release Notes describe status of development of Dasharo (coreboot +
 Heads) firmware for NovaCustom NV4x 12th Gen.
 
+For details about our release process please read
+[Dasharo Standard Release Process](../../dev-proc/standard-release-process.md).
+
+{{ subscribe_form("310eac18-d302-478f-a617-5f5d65e8e0ac",
+"Subscribe to NovaCustom NV4x 12th Gen Dasharo Release Newsletter") }}
+
 ## v0.9.2 - 2025-05-21
 
 Test results for this release can be found