start to convert ad-hoc errors to explicit types

Cargo.lock

@@ -2720,6 +2720,7 @@ dependencies = [
  "stardust-xr",
  "stardust-xr-server-codegen",
  "stereokit-rust",
+ "thiserror 2.0.9",
  "tokio",
  "toml",
  "tracing",
@@ -2771,7 +2772,7 @@ dependencies = [
  "ndk-sys",
  "openxr-sys",
  "stereokit-macros",
- "thiserror 2.0.3",
+ "thiserror 2.0.9",
 ]
 
 [[package]]
@@ -2881,11 +2882,11 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "2.0.3"
+version = "2.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c006c85c7651b3cf2ada4584faa36773bd07bac24acfb39f3c431b36d7e667aa"
+checksum = "f072643fd0190df67a8bab670c20ef5d8737177d6ac6b2e9a236cb096206b2cc"
 dependencies = [
- "thiserror-impl 2.0.3",
+ "thiserror-impl 2.0.9",
 ]
 
 [[package]]
@@ -2901,9 +2902,9 @@ dependencies = [
 
 [[package]]
 name = "thiserror-impl"
-version = "2.0.3"
+version = "2.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f077553d607adc1caf65430528a576c757a71ed73944b66ebb58ef2bbd243568"
+checksum = "7b50fa271071aae2e6ee85f842e2e28ba8cd2c5fb67f11fcb1fd70b276f9e7d4"
 dependencies = [
  "proc-macro2",
  "quote",