fix(web): polyfill Buffer for Privy transfers

.agent/context/20260913T065500Z-privy-browser-buffer.md

@@ -0,0 +1,88 @@
+# Session Context: Privy browser Buffer
+
+## Date/time
+
+- UTC: 2026-09-13T06:55:00Z
+
+## User goal
+
+Fix the Privy approval failure that displays `Buffer is not defined` after the
+user approves an Arc Testnet USDC transfer.
+
+## Original prompt/request
+
+The user supplied screenshots of the Privy approval and failure dialogs and
+asked to fix the issue.
+
+## Assumptions
+
+- The failure is in the browser bundle after approval; the backend settlement
+  and retry behavior must remain unchanged.
+- Existing unrelated backend work in another worktree must remain untouched.
+
+## Plan
+
+1. Reproduce the missing browser-global dependency from the installed Privy
+   transaction path.
+2. Install the existing `buffer` package as an explicit web dependency and
+   initialize it before Privy's lazy-loaded wallet code runs.
+3. Build and run focused web checks.
+
+## Key decisions
+
+- Apply one entry-point polyfill because the installed Privy client contains
+  transaction paths that reference the global Node `Buffer` in the browser.
+- Do not alter wallet selection, transaction parameters, settlement state, or
+  retry behavior.
+
+## Files/components touched
+
+- `apps/web/src/main.tsx`: initialize the browser `Buffer` global before Privy.
+- `apps/web/package.json` and lockfile: make the polyfill a direct dependency.
+
+## Commands/checks
+
+- `pnpm --filter @oneshot/web typecheck` - PASS.
+- `pnpm --filter @oneshot/web test` - PASS, 17 files / 93 tests.
+- `pnpm --filter @oneshot/web build` - PASS; generated entry contains the
+  `globalThis.Buffer` initialization.
+- `pnpm --filter @oneshot/web test:browser` - PASS, 8 Chromium tests; includes
+  an assertion that the browser global is installed.
+- `pnpm lint` - PASS.
+- `pnpm format:check` - PASS.
+- `git diff --check` - PASS.
+- Local Node is v22.23.2 while the repository requests v24.19.0.
+
+## External-doc findings
+
+- None; the installed dependency and observed runtime error establish the
+  compatibility issue.
+
+## Unresolved questions
+
+- A final live Privy approval requires the deployed frontend and the user's
+  wallet session; local checks cover bundle availability and existing wallet
+  behavior.
+
+## Git and PR state
+
+- Branch: `fix/privy-browser-buffer`
+- Base: `origin/develop` at `5e1c9e9210ef22416ee8b62713e9a3e597bb4577`
+- Implementation commit: `4721961d7e55047d120e2d4e51dc3a40b4d520bb`
+- PR: [#126](https://github.com/SWOFART/OneShot/pull/126), draft
+- CI: repository policy, Markdown/Mermaid, and Cloudflare Workers build passed;
+  frontend browser acceptance and ESLint/TypeScript were pending at this snapshot.
+- Production frontend: Cloudflare Worker version
+  `935dfd2b-8fba-4875-964e-7f609c472378`; the public page returned HTTP 200 and
+  its entry bundle contained the `globalThis.Buffer` initialization.
+
+## Review gates
+
+- Gate A: NOT RUN under the user's standing explicit instruction to continue
+  without FreePi; no PASS is claimed.
+- Gate B: NOT RUN
+
+## Handoff/next steps
+
+1. Wait for remaining PR checks and have the user retry one approved testnet
+   transfer; agents do not merge.

apps/web/browser/p5.spec.ts

@@ -104,6 +104,7 @@ async function unlockWorkspace(page: Page): Promise<void> {
 test.describe('resumable job workspace', () => {
   test('keeps the public landing separate from the authenticated cabinet', async ({ page }) => {
     await page.goto('/');
+    expect(await page.evaluate(() => typeof globalThis.Buffer)).toBe('function');
     await expect(
       page.getByRole('heading', { name: 'Resume the job, not the payment.' }),
     ).toBeVisible();

apps/web/package.json

@@ -20,6 +20,7 @@
     "@oneshot/recovery-ui": "workspace:*",
     "@oneshot/settlement-ui": "workspace:*",
     "@privy-io/react-auth": "3.6.1",
+    "buffer": "6.0.3",
     "viem": "2.36.0",
     "react": "19.2.8",
     "react-dom": "19.2.8"

apps/web/src/main.tsx

@@ -1,8 +1,11 @@
+import { Buffer } from 'buffer';
 import { lazy, StrictMode, Suspense } from 'react';
 import { createRoot } from 'react-dom/client';
 import { App } from './App.js';
 import { WorkspaceLoading } from './components/WorkspaceLoading.js';
 
+globalThis.Buffer ??= Buffer;
+
 const DEFAULT_PRIVY_APP_ID = 'cmtqbf5zo013w0cky3r0jqjca';
 const appId =
   import.meta.env.MODE === 'test'