feat(widget): extract AuditTrailViewer into standalone zero-dependency React widget

packages/widget/.gitignore

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+package-lock.json
+node_modules/
+dist/

packages/widget/LICENSE

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+MIT License
+
+Copyright (c) 2026 Nirium Protocol contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/widget/README.md

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+# `@nirium-protocol/audit-trail-viewer`
+
+Standalone, **zero-runtime-dependency** React widget that surfaces Nirium
+anchored audit-trail receipts inside any third-party Web3 dashboard.
+
+Built against the bounty described in [nirium-sdk#12](https://github.com/nirium-protocol/nirium-sdk/issues/12):
+> *Standalone React AuditTrail Viewer Widget — Bounty ($50 USDC).*
+
+## What it does
+
+- Accepts an `appId` and fetches anchored receipts via `GET /api/audit/info`.
+- Displays each receipt's **IPFS CID** and **Stellar tx hash** with working
+  external links (defaulting to `https://ipfs.io/ipfs/<cid>` and
+  `stellar.expert/explorer/public/tx/<hash>` — overridable).
+- Ships Tailwind-friendly class hooks so host apps can restyle freely.
+- Includes a full NPM build setup (`tsup` dual ESM/CJS + TypeScript types).
+- Exposes a dependency-free `fetchAuditInfo()` helper for non-React hosts.
+- Tested with `vitest` + `@testing-library/react` (success / loading / error /
+  empty + click interactions).
+
+## Install
+
+```bash
+npm install @nirium-protocol/audit-trail-viewer
+```
+
+## Usage
+
+```tsx
+import { AuditTrailViewer } from '@nirium-protocol/audit-trail-viewer'
+
+export function Dashboard() {
+  return (
+    <AuditTrailViewer
+      appId="<your-nirium-app-id>"
+      title="Anchored Audit Trail"
+      // Optional: override default Stellar Expert link with custom CTA
+      renderExternalLink={(r) => (
+        <a href={`https://my-explorer.local/tx/${r.stellarTxHash}`}>
+          Verify on My Explorer
+        </a>
+      )}
+    />
+  )
+}
+```
+
+### Non-React usage
+
+```ts
+import { fetchAuditInfo } from '@nirium-protocol/audit-trail-viewer'
+
+const info = await fetchAuditInfo('demo', {
+  baseUrl: 'https://my-nirium-proxy.test',
+})
+console.log(info.receipts)
+```
+
+## Build & test
+
+```bash
+npm install
+npm run build   # tsup → dist/{index.mjs,index.cjs,index.d.ts}
+npm test        # vitest run
+npm run typecheck
+```
+
+## License
+
+MIT.