fix: stabilize learning path, reliability and legacy Windows builds

Unify beginner syntax while preserving compatibility, repair ownership and parser guards, add verified distribution tooling and VC6 Windows 98 build inputs, and clarify documentation and release status. Preserve DOS build-input line endings and exclude generated binaries/caches.

docs/COMPATIBILITY.md

@@ -0,0 +1,36 @@
+# Compatibility syntax
+
+You do not need these spellings for your first programs. Learn the
+[recommended beginner syntax](SYNTAX.md) first. These older forms remain
+supported so existing scripts do not break.
+
+- Older `SET score TO 8` means the same as `SET score 8`.
+- Older `ASK "Number?" AS answer` means the same as `ASK "Number?" answer`.
+- Older `ENDIF`, `DONE`, and `LEARNED` close choices, loops, and functions;
+  the beginner path uses `END` for all three.
+- Older `TEACH add TAKES a, b` and `CALL add WITH 2, 3` correspond to
+  `TEACH add a b` and `DO add 2 3`.
+
+This complete older-style program is covered by an executable compatibility test:
+
+```claro
+TEACH add TAKES a, b
+    RETURN a + b
+LEARNED
+CALL add WITH 2, 3
+SAY RESULT
+SET score TO 8
+ASK "Number?" AS answer
+IF answer = 4
+    DO 2 TIMES
+        SAY score
+    DONE
+ELSE
+    SAY "no"
+ENDIF
+```
+
+Enter `4`. It prints `5`, asks `Number?`, then prints `8` twice.
+
+Do not automatically replace every `AS` or `TO`: commands such as
+`READ FILE "note.txt" AS note` and `ADD "milk" TO items` still need those words.