fix: add comprehensive .dockerignore for security and optimization

[sonusharma6-dsa]

Fixes #426

• Added Python cache patterns (*.pyo, .pytest_cache/)
• Added environment file patterns (.env.*, .env.local)
• Added Git patterns (.gitignore)
• Added frontend dependencies (node_modules/)
• Added documentation patterns (*.md)
• Added IDE files (.vscode/, .idea/)
• Prevents accidental leaking of .env API keys into Docker images
• Reduces Docker image size
• Faster Docker build times

[Copilot]

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[imDarshanGK]

@sonusharma6-dsa update your branch with the latest main changes

[sonusharma6-dsa]

@sonusharma6-dsa update your branch with the latest main changes

Yes doing it

[sonusharma6-dsa]

Hi @imDarshanGK — I've rebased and updated this PR with the latest upstream main. All tests pass locally and the PR is mergeable now. Could you please take a look and, if everything looks good, provide an approving review so it can be merged? Thanks!

[sonusharma6-dsa]

@imDarshanGK, could you please re-request the Copilot PR reviewer from the PR UI so the automated review can re-run? Thanks!