Proj i06/ci baseline setup

[georges-nasrallah]

Summary

Add baseline CI workflows for all services, dependabot for automated dependency updates and pre-commit config for local files hygiene checks. This is a baseline and needs to be modified.

Closes #7

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Motivation & Context

No CI pipelines existed on the repo. PRs could be merged without any automaetd validation

Changes

• Add separate PR CI workflows for auth (Maven + PostgreSQL service), genai (pip install), web-client (build only), and OpenAPI (Redocly lint)
• Add dependabot watching all 5 package ecosystems (github actions, maven, pip, npm x2)
• Add .pre-commit-config.yaml for file hygiene checks (trailing whitespaces, yaml/json validation and scret detection)

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Steps for Testing

1. Open any PR targetting main and verify the 4 CI checks appear and pass.
2. Merge a dependency bump PR from dependabot once it raises one.
3. Run pip install pre-commit && pre-commit install locally, then attempt to commit a file with trailing whitespace.

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Checklist

• [ x] I have self-reviewed the diff
• [ x] Code is clean — no debug statements, commented-out code, or TODOs left behind
• All CI checks pass (build · test · lint)
• Tests added or updated to cover the changes (if needed)
• New env vars added to .env.example
• OpenAPI spec updated and codegen re-run (make -C api generate) if any endpoint changed
• Screenshots or screen recordings attached for any UI changes