feat: add update check, machine-readable output formats, and latency metrics (#18)

- Add UPDATE_CHECK option to notify users of new versions at startup
- Add FORMAT option for machine-readable output (json, yaml, xml)
- Add latency metrics (avg ms) to benchmark results
- Add version injection via Docker build arg
- Add GitHub badges for tag, CodeQL, Tests, Docker Image workflows
- Improve test workflow with continue-on-error for per-step visibility
- Add tests for UPDATE_CHECK and FORMAT validation
- Update README with new options and sample outputs

Author: e7d

.github/workflows/codeql.yml

@@ -1,4 +1,4 @@
-name: "CodeQL"
+name: CodeQL
 
 on:
   push:

.github/workflows/docker-image.yml

@@ -1,4 +1,4 @@
-name: Docker Image CI
+name: Docker Image
 
 on:
   push:
@@ -62,6 +62,14 @@ jobs:
             type=semver,pattern={{major}}
             type=ref,event=pr
             type=raw,value=latest,enable={{is_default_branch}}
+      - name: Determine version
+        id: version
+        run: |
+          if [[ "${{ github.ref }}" == refs/tags/* ]]; then
+            echo "version=${{ github.ref_name }}" >> $GITHUB_OUTPUT
+          else
+            echo "version=${{ github.sha }}" >> $GITHUB_OUTPUT
+          fi
       - name: Build and push Docker image
         uses: docker/build-push-action@v5
         with:
@@ -73,6 +81,8 @@ jobs:
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            VERSION=${{ steps.version.outputs.version }}
       - name: Docker Scout
         id: docker-scout
         if: ${{ github.event_name == 'pull_request' }}