Add cobalt2x2 theme (#6228)

added Cobalt2x2 theme

preview:

<img width="1257" height="812" alt="Screenshot 2026-05-26 at 01 07 42"
src="https://github.com/user-attachments/assets/e2aff5c1-c1d5-4c6c-a0c0-7a7cca1875fb"
/>

Author: kbilkis

.gitmodules

@@ -718,6 +718,10 @@
 	path = extensions/cobalt2
 	url = https://github.com/wesbos/cobalt2-zed.git
 
+[submodule "extensions/cobalt2x2-theme"]
+	path = extensions/cobalt2x2-theme
+	url = https://github.com/kbilkis/cobalt2x2.git
+
 [submodule "extensions/cobol"]
 	path = extensions/cobol
 	url = https://github.com/willswire/zed-cobol.git

extensions.toml

@@ -728,6 +728,10 @@ version = "0.1.0"
 submodule = "extensions/cobalt2"
 version = "0.1.0"
 
+[cobalt2x2-theme]
+submodule = "extensions/cobalt2x2-theme"
+version = "0.0.1"
+
 [cobol]
 submodule = "extensions/cobol"
 version = "0.0.5"