donate: restore original kez diagram for future reference

service/donate.md

@@ -570,6 +570,24 @@ sequenceDiagram
     donate->>civi: Submits donation and perk info
 ```
 
+### Original design
+
+The original sequence diagram built by @kez in January 2023
+([tpo/web/donate-static#107](https://gitlab.torproject.org/tpo/web/donate-static/-/issues/107#note_2872652)) looked like this but shouldn't be
+considered valid anymore:
+
+```mermaid
+sequenceDiagram
+    user->>donate.tpo: visits the donation site
+    donate.tpo->>civicrm: requests the current perks, and prices
+    civicrm->>donate.tpo: stickers: 25, t-shirt: 75...
+    donate.tpo->>user: responds with a fully-rendered donation form
+    user->>donate.tpo: submits the donation form with stripe/paypal details
+    donate.tpo->>donate.tpo: validates form, creates payment contract with stripe/paypal
+    donate.tpo->>civicrm: submits donation and perk info
+    donate.tpo->>user: redirects to donation thank you page
+```
+
 Another possible implementation was this:
 
 ```mermaid
@@ -584,8 +602,7 @@ graph TD
     F --> H(civi gets the donation info from the django backend, and adds it to the civi database without trying to validate the donation amount or perks/swag)
 ```
 
-See [tpo/web/donate-neo#79](https://gitlab.torproject.org/tpo/web/donate-neo/-/issues/79) for the task of
-clarifying those docs.
+See [tpo/web/donate-neo#79](https://gitlab.torproject.org/tpo/web/donate-neo/-/issues/79) for the task of clarifying those docs.
 
 ### Review apps