Update install instructions to use uv sync instead of pip

[palaniappan-r]

No description provided.

[Copilot]

Pull Request Overview

This PR migrates the project's dependency management from pip and requirements.txt files to uv, a modern Python package manager. The main goal is to modernize the development workflow and improve dependency management using uv's faster and more reliable package resolution.

Key changes:

• Replaced requirements.txt files with pyproject.toml using uv's modern dependency specification format
• Updated all installation and build scripts to use uv commands instead of pip
• Upgraded Python version requirement from 3.12 to 3.13

Reviewed Changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
backend/src/agents/retriever_graph.py	Updated import to use newer LangGraph API with CompiledStateGraph
backend/requirements.txt	Removed pip-style requirements file
backend/requirements-test.txt	Removed separate test requirements file
backend/pyproject.toml	Migrated to modern pyproject.toml with uv dependency groups and updated package versions
backend/README.md	Updated installation instructions to use uv sync instead of pip
backend/Makefile	Replaced pip and virtual environment commands with uv equivalents
backend/Dockerfile_slim	Updated Docker build to use uv for dependency management
backend/Dockerfile	Updated Docker build to use uv for dependency management
backend/.python-version	Set Python version to 3.13
README.md	Updated main installation instructions to use uv

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[luarss]

LGTM - just need minor fixes to workflows+Dockerfile. Also please sign off the commits - thanks!

[luarss]

LGTM