Add lite image release build

[Ulthran]

Motivation

• Provide an official lightweight Docker image built and pushed during releases, tagged as the semver -lite variant alongside the normal images.
• Preserve the existing standard release image build and tagging behavior while adding the lite image flow.

Description

• Modify .github/workflows/release.yml to add a new meta_lite metadata extraction step using docker/metadata-action@v5 that produces a type=semver,pattern={{version}}-lite tag.
• Add a Build and push lite Docker image step that builds Dockerfile.lite and pushes tags/labels with docker/build-push-action@v6.
• Keep the original metadata extraction and standard Dockerfile build/push steps unchanged.

Testing

• No automated tests were executed because this change only updates a GitHub Actions workflow and does not modify application code.
• The workflow still depends on the repository run-tests job and references it unchanged, so existing CI test behavior is preserved.

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Codex Task

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.35%. Comparing base (aedc8ad) to head (a9f5265).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #93   +/-   ##
=======================================
  Coverage   46.35%   46.35%           
=======================================
  Files          13       13           
  Lines         563      563           
=======================================
  Hits          261      261           
  Misses        302      302           

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[Copilot]

Pull request overview

This PR adds support for building and publishing a lightweight Docker image variant during releases. The lite image uses Dockerfile.lite (which runs the app in Flask debug mode without database integration) and is tagged with a -lite suffix alongside the standard release images.

Changes:

• Added a new metadata extraction step (meta_lite) that generates semver tags with -lite suffix
• Added a build and push step for the lite Docker image using Dockerfile.lite
• Preserved the existing standard Docker image build workflow unchanged

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