ci(agent-queue): add Gitea shell-ci workflow (shellcheck + syntax + smoke)

Lints agent-queue.sh + bytelyst-cli.sh (shellcheck --severity=error),
syntax-checks all scripts (bash -n) and the Node dashboard (node --check),
and runs a no-agent smoke test (init/add/drain -> failed/). Gitea runner
labels + node:20-bookworm container, path-filtered to the touched files.

.gitea/workflows/shell-ci.yml

@@ -0,0 +1,66 @@
+name: Shell CI — agent-queue + CLI
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'agent-queue/**'
+      - 'bytelyst-cli.sh'
+      - '.gitea/workflows/shell-ci.yml'
+  pull_request:
+    branches: [main]
+    paths:
+      - 'agent-queue/**'
+      - 'bytelyst-cli.sh'
+      - '.gitea/workflows/shell-ci.yml'
+
+concurrency:
+  group: shell-ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  lint:
+    name: shellcheck + syntax
+    runs-on: [ubuntu-latest, bytelyst, hostinger]
+    container:
+      image: node:20-bookworm
+    timeout-minutes: 10
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          github-server-url: https://gitea.bytelyst.com
+
+      - name: Install shellcheck
+        run: |
+          apt-get update -qq
+          apt-get install -y -qq shellcheck
+          shellcheck --version
+
+      - name: shellcheck (errors fail the build)
+        run: |
+          shellcheck --severity=error --shell=bash \
+            agent-queue/agent-queue.sh \
+            bytelyst-cli.sh
+
+      - name: bash syntax check
+        run: |
+          bash -n agent-queue/agent-queue.sh
+          bash -n bytelyst-cli.sh
+
+      - name: node syntax check (dashboard)
+        run: node --check agent-queue/dashboard.mjs
+
+      - name: smoke test (init + add + drain, no real agent)
+        run: |
+          set -euo pipefail
+          export AGENT_QUEUE_ROOT="$PWD/.ci-queue"
+          ./agent-queue/agent-queue.sh init
+          # task with an invalid cwd lands in failed/ without launching any agent
+          printf '%s\n' '---' 'engine: devin' 'cwd: /no/such/dir' 'yolo: true' '---' '# ci' \
+            > /tmp/ci-task.md
+          ./agent-queue/agent-queue.sh add /tmp/ci-task.md
+          ./agent-queue/agent-queue.sh run --once
+          test -f "$AGENT_QUEUE_ROOT"/failed/*.md
+          echo "smoke OK: task routed to failed/ as expected"
+          rm -rf "$AGENT_QUEUE_ROOT"