docs: explain how to track clicks on HSM Dynamic URL buttons (#642)

## Summary

Fixes #265

Adds a "Tracking clicks on a URL button" section right after the Dynamic
URL example in the HSM Templates doc, explaining:

- Why Glific can't show click counts for Static/Dynamic URL buttons:
WhatsApp never sends an event back to Glific when a contact taps a URL
button (unlike Quick Reply buttons, whose taps come back as a message).
- The workaround: embed a unique per-contact value in the Dynamic URL
and route it through a redirect/link-tracking service that logs the
click before forwarding the contact to the real destination.
- A pointer to use Quick Reply buttons instead, if the flow itself needs
to branch on whether the contact engaged.

## Verification

Confirmed against `glific/glific`:
- `lib/glific_web/providers/gupshup/router.ex` only routes an inbound
`button_reply` (Quick Reply) webhook to the message controller — there
is no equivalent inbound route/handler for CTA/URL button taps, so
Glific never learns a URL button was tapped.
- This matches the existing caveat already in this same doc file
("clicks on this button won't be recorded, as the link opens outside and
does not send a response back to the flow"), which this PR generalizes
into concrete guidance.

## Test plan

- [ ] Docs site renders the new section and `:::note` admonition
correctly
- [ ] Reviewer confirms this matches what's told to orgs on
Discord/support

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Documentation**
  * Updated the HSM Templates documentation date.
* Added guidance on tracking URL button clicks: WhatsApp doesn’t report
URL taps back, so use dynamic URLs with a tracking/redirect layer to
record clicks.
* Clarified that for flow logic reacting to engagement, Quick Reply
buttons should be used since they return responses to the flow.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: sangeeta1911 <[email protected]>
Co-authored-by: Claude Sonnet 5 <[email protected]>

Author: 3 people

docs/4. Product Features/06. HSM Templates.md

@@ -112,6 +112,18 @@ Session Window - A session window refers to the 24-hour period following a user'
 
 <img width="" height="496" alt="Screenshot 2026-07-24 at 1 30 48 PM" src="https://github.com/user-attachments/assets/ce900945-aa7b-4d28-b4c2-ffe5c0446791" />
 
+Tracking clicks on a URL button
+
+WhatsApp does not send any signal back to Glific when a contact taps a URL button - the button simply opens the link on the contact's phone. Because of this, Glific has no way to show you how many contacts clicked a Static or Dynamic URL button.
+
+To track clicks yourself, don't point the button straight at your destination page. Instead:
+
+- Use a Dynamic URL to add a unique value for each contact to the link, for example the contact's ID: `https://yourdomain.org/track/{{1}}`
+- Point this link to a redirect page you control, or a link-tracking tool (such as Bitly or Rebrandly), that records every click along with that unique value before sending the contact on to your real destination page.
+- Match the recorded clicks back to your contacts using the unique value, to see who opened the link.
+
+Please Note : If you need the flow itself to react to whether a contact engaged (for example, to send a different follow-up message), use Quick Reply buttons instead of a URL button. Unlike URL buttons, Quick Reply taps send a response back into the flow and can be captured with a `Wait for Response` node.
+
 **WhatsApp Form:** WhatsApp form type buttons can be used to link the WhatsApp forms created and published with Meta.
 
 h. `Attachment type` - Select the attachment type to send an attachment in your HSM template message Ex. Image, Audio, Video, etc.