Add Cloudflare Pages Direct Upload fallback deploy Action (#245)

## Summary

- Adds `.github/workflows/pages-deploy.yml` — Cloudflare Pages Direct
Upload via `npx wrangler@latest pages deploy site/
--project-name=boj-server`
- Bypasses Cloudflare's build system entirely, which was failing because
it reads `.tool-versions` and tries (and fails) to install Idris2
- The Cloudflare dashboard also had `npx wrangler deploy` (the Workers
command, not Pages); this Action uses the correct `wrangler pages
deploy` command

## Why Direct Upload

The Cloudflare build environment:
1. Reads `.tool-versions` via asdf-style tooling
2. Attempts to install Idris2 0.8.0 → fails (not in their build image)
3. Even if it got past that, the deploy command in the dashboard was
`npx wrangler deploy` (Workers-only)

Direct Upload skips all of this: we ship the pre-built `site/` directly
from GitHub Actions.

## Test plan

- [ ] Add `CLOUDFLARE_API_TOKEN` and `CLOUDFLARE_ACCOUNT_ID` secrets to
the repo (Settings → Secrets → Actions)
- [ ] Trigger workflow dispatch or merge to main — verify the Action
deploys successfully
- [ ] Confirm `boj-server.net` is live post-deploy

---
_Generated by [Claude
Code](https://claude.ai/code/session_01XrPAh7eBSUcVKauTVdXH9Y)_

Author: hyperpolymath

.github/workflows/pages-deploy.yml

@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: MPL-2.0
+# Fallback Cloudflare Pages deploy via Direct Upload (wrangler pages deploy).
+# Bypasses the Cloudflare build system entirely — no .tool-versions install
+# attempt, no `wrangler deploy` (Workers command) confusion.
+# Required secrets: CLOUDFLARE_API_TOKEN, CLOUDFLARE_ACCOUNT_ID
+name: Deploy to Cloudflare Pages
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Deploy site/ to Cloudflare Pages
+        run: npx wrangler@latest pages deploy site/ --project-name=boj-server
+        env:
+          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+          CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}