lang: work on various things

- work on new world
  - add file db
  - source_file parsing
  - locs
- fix some test stuff

crates/lang/src/world.rs

@@ -0,0 +1,14 @@
+use std::path::Path;
+
+mod error;
+mod files;
+
+struct World;
+
+impl World {
+    pub fn new(entry_point: &Path) -> Result<Self, WorldCreationError> {
+        todo!()
+    }
+}
+
+enum WorldCreationError {}