chore: setup modern toolchain

Replace Gulp/Browserify/Mocha with tsup/Vitest/Biome.
package.json v2.0.0, ESM+CJS dual exports, Node 20+.
tsconfig.json strict, ES2022 target.

Assisted-by: 🤖 claude-opus-4-6@default

Author: cardil

.gitignore

@@ -1,28 +1,28 @@
+# Dependencies
+node_modules/
+
+# Build output
+dist/
+
+# Coverage
+coverage/
+
 # Logs
-logs
 *.log
 
 # Runtime data
-pids
 *.pid
 *.seed
 
-# Directory for instrumented libs generated by jscoverage/JSCover
-lib-cov
-
-# Coverage directory used by tools like istanbul
-coverage
-
-# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
-.grunt
-
-# node-waf configuration
-.lock-wscript
+# OS files
+.DS_Store
+Thumbs.db
 
-# Compiled binary addons (http://nodejs.org/api/addons.html)
-build/Release
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
 
-# Dependency directory
-# https://www.npmjs.org/doc/misc/npm-faq.html#should-i-check-my-node_modules-folder-into-git
-node_modules
-target/
+# Temp
+.ai/

biome.json

@@ -0,0 +1,20 @@
+{
+  "$schema": "https://biomejs.dev/schemas/1.9.0/schema.json",
+  "organizeImports": {
+    "enabled": true
+  },
+  "formatter": {
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineWidth": 100
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true
+    }
+  },
+  "files": {
+    "ignore": ["dist", "coverage", "node_modules"]
+  }
+}