ci: pull-based deploy to the Pi via rolling dev release

The Pi is on a closed travel-router LAN, so push-based deploy from a
runner can't reach it. Switch to pull: the runner builds + publishes,
the Pi fetches.

- build-dev.yaml: after the arm64 build, publish the binary + sha256 +
  version.txt to a rolling "dev" Gitea release (replaces the
  upload-artifact + repository_dispatch -> deploy-dev hop)
- remove deploy-dev.yaml (push/scp-based deploy no longer used)
- scripts/pi-update.sh: poll the dev release, verify sha256, install via
  deploy.sh (backup/restart/rollback); only updates when version changes
- scripts/remoterig-update.{service,timer}: run the updater every 5 min
- setup-pi.sh: install deploy.sh + pi-update.sh + update.env template +
  the updater timer; summary now reflects the pull flow
- README: document the pull-based CI/CD; fix stale GOARM=6 (Zero 2 W is
  arm64 on 64-bit OS / arm GOARM=7 on 32-bit)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/build-dev.yaml

@@ -7,8 +7,8 @@ on:
   workflow_dispatch:
 
 env:
-  GO_VERSION: "1.23"
-  NODE_VERSION: "20"
+  GO_VERSION: "1.25"
+  NODE_VERSION: "22"
   BINARY_NAME: remoterig
 
 jobs:
@@ -39,25 +39,34 @@ jobs:
             go build -ldflags="-s -w -X main.version=${GITHUB_SHA:0:8}" \
             -o ${{ env.BINARY_NAME }} ./cmd/server
 
-      - name: Upload build artifact
-        uses: actions/upload-artifact@v4
-        with:
-          name: ${{ env.BINARY_NAME }}
-          path: ${{ env.BINARY_NAME }}
-          retention-days: 5
+      # Pull-based deploy: publish the binary to a rolling "dev" release.
+      # The Pi polls this release and self-updates (scripts/pi-update.sh);
+      # the runner never needs to reach the closed RemoteRig network.
+      - name: Publish to rolling dev release
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SERVER: ${{ github.server_url }}
+          REPO: ${{ github.repository }}
+          SHA: ${{ github.sha }}
+        run: |
+          set -euo pipefail
+          command -v jq >/dev/null || sudo apt-get update -qq && sudo apt-get install -y -qq jq
+          API="$SERVER/api/v1/repos/$REPO"
+          AUTH="Authorization: token $TOKEN"
+          VERSION="${SHA:0:8}"
+          echo "$VERSION" > version.txt
+          sha256sum "$BINARY_NAME" | awk '{print $1}' > "$BINARY_NAME.sha256"
 
-      - name: Trigger deploy workflow
-        if: success()
-        uses: actions/github-script@v7
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          script: |
-            await github.rest.repos.createDispatchEvent({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              event_type: 'dev-build-success',
-              client_payload: {
-                sha: context.sha,
-                ref: context.ref
-              }
-            })
+          # Roll the "dev" release forward to this commit (delete old release + tag).
+          REL_ID=$(curl -sf -H "$AUTH" "$API/releases/tags/dev" | jq -r '.id // empty' || true)
+          [ -n "$REL_ID" ] && curl -sf -X DELETE -H "$AUTH" "$API/releases/$REL_ID" || true
+          curl -sf -X DELETE -H "$AUTH" "$API/tags/dev" || true
+
+          REL_ID=$(curl -sf -X POST -H "$AUTH" -H "Content-Type: application/json" "$API/releases" \
+            -d "{\"tag_name\":\"dev\",\"target_commitish\":\"$SHA\",\"name\":\"dev ($VERSION)\",\"body\":\"Rolling dev build $SHA\",\"prerelease\":true}" \
+            | jq -r '.id')
+
+          for f in "$BINARY_NAME" "$BINARY_NAME.sha256" version.txt; do
+            curl -sf -X POST -H "$AUTH" -F "attachment=@$f" "$API/releases/$REL_ID/assets?name=$f"
+          done
+          echo "Published dev release $VERSION"