feat: converter keeps layers of screens and camera, perspective, matrix calls; That New Teacher runs its own text-tag libraries

onlayer on show/hide/call screen and `camera <layer>` reach the player, `perspective`
is an ATL property now, RotateMatrix/OffsetMatrix/ScaleMatrix, Text.set_text and
renpy.fetch are accepted. The text-effect modules of That New Teacher are no longer
skipped (only the shader-based wave tag is).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

backend/app/converter/rpy_parser.py

@@ -1227,8 +1227,10 @@ class RpyParser:
     def st_camera(self, line: Line) -> list[Node]:
         c = self.cursor(line)
         c.keyword("camera")
-        c.word() if not c.peek("at") and not c.peek(":") else None
+        layer = c.word() if not c.peek("at") and not c.peek(":") else None
         node: Node = {"op": "camera", "at": []}
+        if layer:
+            node["layer"] = layer
         if c.keyword("at"):
             for item in _split_top(c.until(set(), ":")):
                 node["at"].append(self.transform_ref(item, line))
@@ -1466,8 +1468,10 @@ class RpyParser:
     def screen_call(self, c: Cursor, line: Line) -> Node | None:
         """``name(args)`` after `call/show screen`; trailing `nopredict` and `with` are ignored."""
         source = re.split(r"\s+(?:nopredict|with)\b", c.rest(), maxsplit=1)[0].strip()
-        # `onlayer name` only picks the stacking layer; the player keeps every screen in one layer
-        source = re.sub(r"\s+onlayer\s+\w+\s*$", "", source)
+        layer_match = re.search(r"\s+onlayer\s+(\w+)\s*$", source)
+        layer = layer_match.group(1) if layer_match else None
+        if layer_match:
+            source = source[:layer_match.start()]
         call = self.expr(source, line) if source else None
         if call is None:
             self.d.warn("Не разобран вызов screen", self.where(line))
@@ -1480,7 +1484,10 @@ class RpyParser:
             self.d.warn("Не разобран вызов screen", self.where(line))
             return None
         self.use_screen(name)
-        return {"name": name, "args": args, "kw": kw}
+        found: Node = {"name": name, "args": args, "kw": kw}
+        if layer:
+            found["layer"] = layer
+        return found
 
     def st_scene(self, line: Line) -> list[Node]:
         c = self.cursor(line)
@@ -1521,7 +1528,10 @@ class RpyParser:
             name = c.word()
             if not name:
                 return []
-            return [{"op": "hide_screen", "name": name}]  # hiding a screen that does not exist is harmless
+            hidden: Node = {"op": "hide_screen", "name": name}  # hiding a screen that does not exist is harmless
+            if c.keyword("onlayer"):
+                hidden["layer"] = c.word()
+            return [hidden]
         spec = self.image_spec(c, line)
         node: Node = {"op": "hide", "tag": spec.get("tag", spec.get("name", [""])[0])}
         self.show_clauses(c, line, node)