refactor(tailshare): keep node types out of the browser project

Adding node types for the new unit tests applied them to every file, so
browser code could import a node builtin and still typecheck. Split the
project: the app compiles with no ambient type packages and excludes the
tests, and a test project adds node types back for the test files alone.

Verified by importing node:fs into a browser module and confirming the
app project rejects it while the test project does not.

Co-Authored-By: claude-opus-5 <noreply@anthropic.com>

packages/tailshare/package.json

@@ -6,7 +6,7 @@
     "dev": "webpack serve --mode development",
     "build": "NODE_ENV=production webpack --mode production",
     "test": "tsx --test --test-force-exit 'src/**/*.test.ts'",
-    "typecheck": "tsc --noEmit"
+    "typecheck": "tsc --project tsconfig.json --noEmit && tsc --project tsconfig.test.json --noEmit"
   },
   "dependencies": {
     "@mantine/core": "^9.3.1",

packages/tailshare/tsconfig.json

@@ -5,7 +5,7 @@
     "module": "ESNext",
     "moduleResolution": "bundler",
     "jsx": "react-jsx",
-    "types": ["node"],
+    "types": [],
     "strict": true,
     "noEmit": true,
     "isolatedModules": true,
@@ -14,5 +14,6 @@
     "erasableSyntaxOnly": true,
     "skipLibCheck": true
   },
-  "include": ["src"]
+  "include": ["src"],
+  "exclude": ["src/**/*.test.ts"]
 }

packages/tailshare/tsconfig.test.json

@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "types": ["node"]
+  },
+  "include": ["src/**/*.test.ts"],
+  "exclude": []
+}