ci: add GitHub Actions workflow + CI badge

.github/workflows/ci.yml runs on push/PR to main with three jobs:
  - compose-validate: 'docker compose config --quiet' to catch yaml /
    interpolation errors.
  - markdown-lint: DavidAnson/markdownlint-cli2-action over README,
    README.es, CHANGELOG, CONTRIBUTING, SECURITY. Disables MD013 (line
    length) and MD033 (raw HTML) since both READMEs use HTML img tags
    and long lines on purpose.
  - shellcheck: lints scripts/ via ludeeus/action-shellcheck.

Added a CI badge to both READMEs next to the existing badge banner.

Author: cartesiosson

.github/workflows/ci.yml

@@ -0,0 +1,58 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  compose-validate:
+    name: docker compose config (syntax)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Validate docker-compose.yml syntax
+        run: |
+          # Substitute env from .env.example so the validator has values
+          cp .env.example .env
+          docker compose config --quiet
+
+  markdown-lint:
+    name: markdown lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Lint Markdown files
+        uses: DavidAnson/markdownlint-cli2-action@v16
+        with:
+          globs: |
+            README.md
+            README.es.md
+            CHANGELOG.md
+            CONTRIBUTING.md
+            SECURITY.md
+          config: |
+            {
+              "default": true,
+              "MD013": false,
+              "MD033": false,
+              "MD041": false,
+              "MD024": { "siblings_only": true }
+            }
+
+  shellcheck:
+    name: shellcheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Run shellcheck on scripts/
+        uses: ludeeus/action-shellcheck@2.0.0
+        with:
+          scandir: ./scripts

README.es.md

@@ -11,6 +11,7 @@
   <img src="https://img.shields.io/badge/Throughput-~18%20tok%2Fs-43A047?style=flat-square" alt="~18 tok/s">
   <img src="https://img.shields.io/badge/Coste%20por%20token-%240-43A047?style=flat-square" alt="$0 token cost">
   <img src="https://img.shields.io/badge/Licencia-MIT-yellow?style=flat-square" alt="MIT License">
+  <a href="https://github.com/cartesiosson/openvino-agent-stack/actions/workflows/ci.yml"><img src="https://github.com/cartesiosson/openvino-agent-stack/actions/workflows/ci.yml/badge.svg" alt="CI"></a>
 </p>
 
 > 🌍 **English version**: [README.md](README.md)

README.md

@@ -11,6 +11,7 @@
   <img src="https://img.shields.io/badge/Throughput-~18%20tok%2Fs-43A047?style=flat-square" alt="~18 tok/s">
   <img src="https://img.shields.io/badge/Token%20cost-%240-43A047?style=flat-square" alt="$0 token cost">
   <img src="https://img.shields.io/badge/License-MIT-yellow?style=flat-square" alt="MIT License">
+  <a href="https://github.com/cartesiosson/openvino-agent-stack/actions/workflows/ci.yml"><img src="https://github.com/cartesiosson/openvino-agent-stack/actions/workflows/ci.yml/badge.svg" alt="CI"></a>
 </p>
 
 > 🌍 **Versión en español**: [README.es.md](README.es.md)