feat(react): dual dist build strips dev-only effects from production

.changeset/dev-only-effect-dual-build.md

@@ -0,0 +1,14 @@
+---
+'@primer/react': patch
+---
+
+Dev-only effects (the `if (__DEV__) { useEffect(...) }` pattern with an
+`eslint-disable react-hooks/rules-of-hooks` comment) are now expressed via a
+new internal `useDevOnlyEffect` hook, and the published package ships dual
+`dist/development/` and `dist/production/` artifacts. Consumers' bundlers
+automatically pick the right one via `package.json` `exports` `development` /
+`production` import conditions, and the production artifact has every
+`useDevOnlyEffect(...)` call statement — including the effect-callback closure
+and the deps array — removed at publish time by a small babel plugin. The
+public API is unchanged; this is purely a runtime/byte-size win in production
+builds.

packages/react/package.json

@@ -3,28 +3,38 @@
   "type": "module",
   "version": "38.24.0",
   "description": "An implementation of GitHub's Primer Design System using React",
-  "main": "./dist/index.js",
-  "module": "./dist/index.js",
+  "main": "./dist/production/index.js",
+  "module": "./dist/production/index.js",
   "exports": {
     ".": {
       "types": "./dist/index.d.ts",
-      "default": "./dist/index.js"
+      "development": "./dist/development/index.js",
+      "production": "./dist/production/index.js",
+      "default": "./dist/production/index.js"
     },
     "./experimental": {
       "types": "./dist/experimental/index.d.ts",
-      "default": "./dist/experimental/index.js"
+      "development": "./dist/development/experimental/index.js",
+      "production": "./dist/production/experimental/index.js",
+      "default": "./dist/production/experimental/index.js"
     },
     "./deprecated": {
       "types": "./dist/deprecated/index.d.ts",
-      "default": "./dist/deprecated/index.js"
+      "development": "./dist/development/deprecated/index.js",
+      "production": "./dist/production/deprecated/index.js",
+      "default": "./dist/production/deprecated/index.js"
     },
     "./next": {
       "types": "./dist/next/index.d.ts",
-      "default": "./dist/next/index.js"
+      "development": "./dist/development/next/index.js",
+      "production": "./dist/production/next/index.js",
+      "default": "./dist/production/next/index.js"
     },
     "./test-helpers": {
       "types": "./dist/utils/test-helpers.d.ts",
-      "default": "./dist/test-helpers.js"
+      "development": "./dist/development/test-helpers.js",
+      "production": "./dist/production/test-helpers.js",
+      "default": "./dist/production/test-helpers.js"
     },
     "./generated/components.json": "./generated/components.json",
     "./generated/hooks.json": "./generated/hooks.json"