feat: add version and git commit to /api/stats and /api/health

Node.js: reads version from package.json, commit from .git-commit file
or git rev-parse --short HEAD at runtime, with unknown fallback.

Go: uses -ldflags build-time variables (Version, Commit) with fallback
to .git-commit file and git command at runtime.

Dockerfile: copies .git-commit if present (CI bakes it before build).
Dockerfile.go: passes APP_VERSION and GIT_COMMIT as build args to ldflags.
deploy.yml: writes GITHUB_SHA to .git-commit before docker build steps.
docker-compose.yml: passes build args to Go staging build.

Tests updated to verify version and commit fields in both endpoints.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/deploy.yml

@@ -176,6 +176,7 @@ jobs:
 
       - name: Build image
         run: |
+          echo "${GITHUB_SHA::7}" > .git-commit
           docker build -t meshcore-analyzer:latest .
           echo "Built $(git rev-parse --short HEAD)"
 
@@ -249,6 +250,9 @@ jobs:
       - name: Deploy Go staging
         run: |
           echo "Building Go staging image..."
+          echo "${GITHUB_SHA::7}" > .git-commit
+          APP_VERSION=$(node -p "require('./package.json').version") \
+          GIT_COMMIT="${GITHUB_SHA::7}" \
           docker compose --profile staging-go build staging-go
 
           echo "Replacing Go staging container..."