chore: add .env.enterprise and reports/ to .gitignore

[ltianyi992]

Closes #787

Summary

• Adds .env.enterprise to prevent accidental commit of enterprise environment secrets
• Adds reports/ to prevent committing generated report output files

Test plan

• Verify .env.enterprise is ignored by git
• Verify reports/ directory is ignored by git

[gemini-code-assist]

Code Review

This pull request updates the .gitignore file to include .env.enterprise and a new reports/ directory for generated reports. The review feedback suggests using a wildcard pattern .env.* to more robustly exclude environment-specific configuration files and prevent the accidental exposure of sensitive credentials.

[gemini-code-assist]

Using a wildcard pattern like .env.* is more robust than listing specific environment files. This ensures that any environment-specific configuration files (e.g., .env.local, .env.production) are automatically ignored, reducing the risk of accidentally committing sensitive credentials.

.env.*