Add maiko, notecards, loops, test as git submodules

Removes maiko/ from .gitignore so it can be tracked as a submodule.
Each submodule is pinned to the current HEAD of its default branch
(master for maiko/test, main for notecards/loops).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -5,9 +5,6 @@ tmp/*
 # releases directory
 releases/*
 
-# maiko directory
-maiko/
-
 
 # all PDFs (those explicitly checked in aren't ignored
 # normally when you have derived files, you ignore them from git

.gitmodules

@@ -0,0 +1,16 @@
+[submodule "maiko"]
+	path = maiko
+	url = https://github.com/Interlisp/maiko
+	branch = master
+[submodule "notecards"]
+	path = notecards
+	url = https://github.com/Interlisp/notecards
+	branch = main
+[submodule "loops"]
+	path = loops
+	url = https://github.com/Interlisp/loops
+	branch = main
+[submodule "test"]
+	path = test
+	url = https://github.com/Interlisp/test
+	branch = master