switch header from Authorization to X-PIWIGO-API

Piwigo-Web-API.md

@@ -23,6 +23,9 @@ on Piwigo demo](https://demo1.piwigo.com/tools/ws.htm).
 Since Piwigo 16, each user can generate one or more personal API keys from their profile.
 These keys allow secure, stateless access to the Piwigo web API without requiring a user session.
 
+⚠️ Important change between Piwigo 16.0.0 and 16.1.0:
+- Use the `X-PIWIGO-API` header instead of `Authorization` when sending API keys.
+
 ### Generate an API key
 
  1. Log in to your Piwigo account.
@@ -33,15 +36,15 @@ These keys allow secure, stateless access to the Piwigo web API without requirin
 
 ### Use an API key
 
-* To authenticate your API requests, use the `Authorization` HTTP header:\
-`Authorization: pkid-XXXXXXXX-XXXXXXXXXXXX:YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY`
+* To authenticate your API requests, use the `X-PIWIGO-API` HTTP header:\
+`X-PIWIGO-API: pkid-XXXXXXXX-XXXXXXXXXXXX:YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY`
   * `pkid-XXX...` = public identifier of the key
   * `YYYYY...` = secret key\
   _Don't forget `:` between them_
 
 * Example with curl:
 ```
-curl -H "Authorization: pkid-20250609-abcdef1234567890:0123456789abcdef0123456789abcdef01234567" \
+curl -H "X-PIWIGO-API: pkid-20250609-abcdef1234567890:0123456789abcdef0123456789abcdef01234567" \
   -d "method=pwg.categories.getList" \
   -d "format=json" \
   https://your-piwigo/ws.php
@@ -60,7 +63,7 @@ curl -H "Authorization: pkid-20250609-abcdef1234567890:0123456789abcdef012345678
 Test your keys:
 
 Use the built-in tool `https://your-piwigo/tools/ws.htm`\
-An `Authorization` field lets you test your requests with an API key.
+An `X-PIWIGO-API` field lets you test your requests with an API key.
 
 Best practices:
 * Use a different key for each application or script.