feat: add --dry-run flag for CLI run command

[SouravVerma-art]

• add --dry-run flag to preview translation tasks without execution
• show detailed file analysis: source/target strings, changes breakdown
• display summary with total strings to translate
• skip authentication and API initialization in dry-run mode
• support all existing filter flags (--target-locale, --bucket, --file, --key)

this feature allows users to:

• preview which files would be translated
• see how many strings would be affected
• estimate potential costs before running actual translation
• verify configuration without making changes

[sumitsaurabh927]

@SouravVerma-art please resolve comments

[sumitsaurabh927]

@SouravVerma-art please go through the comments and resolve them

[github-actions[bot]]

Hey @SouravVerma-art! Just checking in - are you still working on this PR? We noticed there are some comments that may need addressing. If you need more time, no problem! Just let us know. If we don't hear back within a week, we'll close this to keep the repo tidy, but you can always reopen when ready.

[github-actions[bot]]

Closing this PR as stale to keep the repo clean. Feel free to reopen or create a new PR once you're ready to continue. Thanks for your contribution!