Feature/improve documentation

[sobuur0]

Description of the change

Improve documentation and development setup

What Changed

• created comprehensive monorepo README: Replaced generic flutter template with developer focused guide
• Added development setup instructions: Step by step guide for contributors including code generation requirements
• Documented common issues and solutions: Troubleshooting section for setup problems developers encounter
• Updated gitignore: Added fvm and vscode support for better developer experience
• Made build scripts executable: Fixed permissions on development scripts

Why This Matters

• Solves contributor onboarding issues: New developers can now set up the project without hitting import/generation errors
• Explains monorepo structure: Clear overview of the 4 packages and their purposes

Type of change

• [ ] Bug fix (non-breaking change that fixes an issue)
• [x] New feature (non-breaking change that adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Related issues

Issue links go here

Checklists

Development

• [x] Lint rules pass locally
• [x] The code changed/added as part of this pull request has been covered with tests

Code review

• [x] This pull request has a descriptive title and information useful to a reviewer
• [ ] Issue from task tracker has a link to this pull request

Requesting review from repo owners:
@ahmedAlaaInstabug @AndrewAminInstabug