refactor: tsdown again

Author: mkvlrn

.editorconfig

@@ -1,24 +1,26 @@
-root=true
+root = true
 
 [*]
 end_of_line = lf
 insert_final_newline = true
-indent_style = space
-indent_size = 2
 trim_trailing_whitespace = true
 max_line_length = 100
-
-[*.md]
-trim_trailing_whitespace = false
-
-[*.{cs,py}]
-indent_size = 4
 indent_style = space
+indent_size = 2
+tab_width = 2
 
 [*.go]
-indent_size = 4
 indent_style = tab
+indent_size = 4
+tab_width = 4
 
-[Makefile]
+[*.{cs,py}]
 indent_size = 4
+
+[Makefile]
 indent_style = tab
+indent_size = 4
+tab_width = 4
+
+[*.md]
+trim_trailing_whitespace = false

package.json

@@ -19,15 +19,9 @@
   "engines": {
     "node": "24"
   },
-  "imports": {
-    "#*": {
-      "dev": "./src/*.ts",
-      "default": "./build/*.js"
-    }
-  },
   "scripts": {
-    "build": "rm -rf build && tsc --project tsconfig.build.json --listEmittedFiles",
-    "dev": "tsx -C dev --watch src/main.ts",
+    "build": "tsdown",
+    "dev": "tsx --watch src/main.ts",
     "start": "node build/main.js",
     "test": "vitest",
     "biome-check": "biome check --diagnostic-level=warn --no-errors-on-unmatched",
@@ -51,6 +45,7 @@
     "vitest": "^4.0.16"
   },
   "dependencies": {
-    "@mkvlrn/result": "^5.0.4"
+    "@mkvlrn/result": "^5.0.4",
+    "tsdown": "^0.18.4"
   }
 }