[dashboards] open-brain-dashboard-next: add Cloudflare Workers deploy support

Adds the @opennextjs/cloudflare adapter so the dashboard can deploy to
Cloudflare Workers alongside the open-brain-rest gateway, keeping the
whole second-brain stack on a single platform. The older
@cloudflare/next-on-pages adapter caps at Next 15.5.x and doesn't
support this dashboard's Next 16, so OpenNext is the only path that
works without a major-version downgrade.

Builds on the next 16.2.4 patch bump merged from
contrib/tswicegood/dashboard-next-bump (which clears OpenNext's
next>=16.2.3 peer dep on its own).

Changes:
- @opennextjs/cloudflare and wrangler as dev deps.
- open-next.config.ts and wrangler.jsonc — the two config files
  OpenNext needs at the project root. Worker name defaults to
  ob-dashboard; deployers can rename in wrangler.jsonc.
- README: new "Deploy to Cloudflare Workers" subsection alongside
  the existing Vercel one, including the build-time vs. runtime
  distinction for NEXT_PUBLIC_API_URL vs. SESSION_SECRET (catching
  that was the difference between a working deploy and a half-
  configured one).
- .gitignore: exclude .open-next/ and .wrangler/ build artifacts.

Vercel deploy path is unchanged; this is purely additive.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: tswicegood

dashboards/open-brain-dashboard-next/.gitignore

@@ -1,6 +1,8 @@
 node_modules/
 .next/
 .vercel/
+.open-next/
+.wrangler/
 .env
 .env.local
 .env.local.example

dashboards/open-brain-dashboard-next/README.md

@@ -93,6 +93,30 @@ Or connect the folder to Vercel via the dashboard. Set the environment variables
 > [!TIP]
 > The free Vercel tier is sufficient. The dashboard makes server-side API calls to your Open Brain REST endpoint — there's no heavy compute.
 
+### Step 5 (alternative): Deploy to Cloudflare Workers (optional)
+
+If you're already on Cloudflare for the [`open-brain-rest`](../../integrations/cloudflare-rest-worker/) gateway, you can host the dashboard on the same platform via the [`@opennextjs/cloudflare`](https://opennext.js.org/cloudflare) adapter. The older `@cloudflare/next-on-pages` adapter caps at Next 15.5.x and doesn't support this dashboard's Next 16.
+
+The repo ships the two config files this needs out of the box (`open-next.config.ts` and `wrangler.jsonc`); rename the Worker in `wrangler.jsonc` if you want something other than `ob-dashboard`.
+
+```bash
+# 1. Make sure .env has NEXT_PUBLIC_API_URL set — it's read at *build*
+#    time and baked into the client bundle.
+npx opennextjs-cloudflare build
+
+# 2. First-time deploy creates the Worker.
+npx opennextjs-cloudflare deploy
+
+# 3. Set SESSION_SECRET as a *runtime* secret on the deployed Worker.
+#    (NEXT_PUBLIC_API_URL is build-time only, so no Worker secret for it.)
+wrangler secret put SESSION_SECRET --name ob-dashboard
+```
+
+The dashboard ends up at `https://ob-dashboard.<your-cf-subdomain>.workers.dev`.
+
+> [!TIP]
+> `NEXT_PUBLIC_API_URL` is build-time, `SESSION_SECRET` is runtime. If you change the API URL later you have to rebuild and redeploy; rotating the session secret only needs `wrangler secret put`.
+
 ## Expected Outcome
 
 When working correctly:

dashboards/open-brain-dashboard-next/open-next.config.ts

@@ -0,0 +1,3 @@
+import { defineCloudflareConfig } from "@opennextjs/cloudflare";
+
+export default defineCloudflareConfig({});