fix(build): remove --omit=dev from npm ci in Dockerfile frontend-builder stage

The Tailwind CSS CLI is a devDependency in frontend/package.json. Using
`npm ci --omit=dev` skipped installing it, causing the Docker build to
fail with 'sh: tailwindcss: not found' at the `npm run build` step.

Since this is a multi-stage build where the frontend-builder stage is
discarded after compilation, all dependencies (including devDependencies)
are needed during the build but do not bloat the final image.

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
Agent-Logs-Url: https://github.com/christianlouis/DocuElevate/sessions/f16fabb4-4d8c-48e3-8d26-c2d38cc7129f

Dockerfile

@@ -34,7 +34,7 @@ WORKDIR /frontend
 
 # Install dependencies first (layer-cached unless package.json/lockfile changes)
 COPY frontend/package.json frontend/package-lock.json ./
-RUN npm ci --omit=dev
+RUN npm ci
 
 # Copy source files and compile Tailwind CSS
 COPY frontend/ ./