Add issues #16–#23

#16 multiline shell commands
#17 _ scope (global vs local)
#18 path expansion (~)
#19 nested commands trigger prompt2
#20 simplify backtick return value
#21 prompt redesign
#22 implicit interactive commands (drop ! prefix)
#23 general cleanup and refactor

issues/23-cleanup-refactor.md

@@ -0,0 +1,20 @@
+# 23 — General cleanup and refactor
+
+**Status:** open
+
+Housekeeping pass over the codebase.
+
+## Function names
+
+Function names should be reviewed and improved for consistency and clarity.
+
+## Global namespace (`_G`)
+
+Review what's exposed in `_G`. Do we need to expose everything? Candidates for cleanup:
+
+- `__command` — internal, could be hidden
+- `__interactive` — internal, could be hidden
+- `__getenv` / `__setenv` — internal, could be hidden
+- `__builtins` — should this be user-facing or internal?
+
+Consider whether internal functions should live in a single `__lush` table or use the registry instead of polluting globals.