chore(infra) - migrate to typescript v7 && tsdown

.cursor/BUGBOT.md

@@ -535,7 +535,7 @@ This will:
 
 - **Documentation**: Check `README.md` and flow-specific READMEs
 - **Architecture questions**: Review this document and `src/` structure
-- **Build issues**: Check `tsup.config.ts` and `package.json` scripts
+- **Build issues**: Check `tsdown.config.ts` and `package.json` scripts
 - **Test issues**: See `vitest.config.ts` and `vitest-setup.ts`
 - **CI issues**: Review `.github/workflows/ci.yml`
 - **Ask the team**: When in doubt, ask for clarification before merging

.cursor/environment.json

@@ -4,7 +4,7 @@
     {
       "name": "lib-watch",
       "command": "npm run dev",
-      "description": "tsup watch build for the main package"
+      "description": "tsdown watch build for the main package"
     },
     {
       "name": "example-app",

.github/workflows/size-check.yml

@@ -8,7 +8,7 @@ on:
       - 'src/**'
       - 'package.json'
       - 'package-lock.json'
-      - 'tsup.config.ts'
+      - 'tsdown.config.ts'
       - '.sizelimit.json'
 
 permissions:

.github/workflows/update-badge.yml

@@ -8,7 +8,7 @@ on:
       - 'src/**'
       - 'package.json'
       - 'package-lock.json'
-      - 'tsup.config.ts'
+      - 'tsdown.config.ts'
   workflow_dispatch:
 
 permissions:

.sizelimit.json

@@ -4,8 +4,8 @@
     "totalGzip": 350000,
     "css": 150000,
     "cssGzip": 25000,
-    "maxChunkSize": 50000,
-    "maxChunkSizeGzip": 15000
+    "maxChunkSize": 100000,
+    "maxChunkSizeGzip": 30000
   },
   "exclude": ["**/*.map", "**/*.d.ts"],
   "warningThreshold": 0.9

CLAUDE.md

@@ -11,8 +11,8 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 ## Commands
 
 ```bash
-npm run dev            # tsup watch build (link this package into example/ for live dev)
-npm run build          # production bundle (tsup)
+npm run dev            # tsdown watch build (link this package into example/ for live dev)
+npm run build          # production bundle (tsdown)
 npm test               # vitest (jsdom). Single test: npx vitest run path/to/file.test.tsx
 npm run test:coverage  # coverage with thresholds from scripts/coverage-utils
 npm run type-check     # tsc --noEmit
@@ -89,7 +89,7 @@ Tailwind v4 (`@tailwindcss/postcss`) + CSS variables. Public component classes a
 
 ### Package exports & bundle
 
-[package.json](package.json) ships **multiple ESM entry points** — `.`, `./internals`, `./default-components`, `./flows/*`, `./styles`, `./styles.css`, `./index.css`. Tsup builds each as a separate chunk ([tsup.config.ts](tsup.config.ts)), `react`/`react-dom` are externals, `react-hook-form` + `@hookform/resolvers` are bundled (`noExternal`). Bundle limits in [.sizelimit.json](.sizelimit.json) are enforced in CI by `.github/workflows/size-check.yml`. The `internals` entry point has **no semver guarantees**.
+[package.json](package.json) ships **multiple ESM entry points** — `.`, `./internals`, `./default-components`, `./flows/*`, `./styles`, `./styles.css`, `./index.css`. Tsup builds each as a separate chunk ([tsdown.config.ts](tsdown.config.ts)), `react`/`react-dom` are externals, `react-hook-form` + `@hookform/resolvers` are bundled (`noExternal`). Bundle limits in [.sizelimit.json](.sizelimit.json) are enforced in CI by `.github/workflows/size-check.yml`. The `internals` entry point has **no semver guarantees**.
 
 ## Conventions worth knowing