Mark 4.0.6 as released (#23994)

Update changelog and emscripten-version.txt [ci skip]

Author: emscripten-bot

ChangeLog.md

@@ -18,8 +18,11 @@ to browse the changes between the tags.
 
 See docs/process.md for more on how version tagging works.
 
-4.0.6 (in development)
+4.0.7 (in development)
 ----------------------
+
+4.0.6 - 03/26/25
+----------------
 - Added support for applying path prefix substitution to the sources of the
   source map : use `-sSOURCE_MAP_PREFIXES=["<old>=<new>"]` with `-gsource-map`.
   Alternatively, you can now embed the sources content into the source map file

emscripten-version.txt

@@ -1 +1 @@
-4.0.6-git
+4.0.7-git