feat: add support for 'mgit add .' to stage all unstaged files

[navneetsingh-dev]

🚀 Feature Description

Currently, mgit add requires individual file paths to stage changes. Adding support for the . syntax (mgit add .) would allow users to recursively stage all modified, deleted, and untracked files in the current working directory and its subdirectories.

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🎯 Motivation & Use Case

• Improved Developer UX: Standard Git functionality allows git add . to quickly stage all changes. Supporting this in mgit aligns with standard Git workflow expectations.
• Efficiency: Eliminates the need to manually stage files one by one when working on multi-file changes.

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🛠️ Proposed Solution / Behavior

• Command: mgit add .
• Expected Result:
  1. Traverses the current directory recursively.
  2. Respects .mgitignore (or .gitignore if implemented).
  3. Adds all new, untracked, and modified files to the staging index.