Support automatic flag assignment by file path for monorepos

[Kobby-Bawuah]

What product do you want to improve? Codecov GitHub Action / Uploader

Is your feature request related to a problem? Please describe. In monorepos, it's tedious to manually create separate test + upload steps with -F flags for each package just to use carryforward. Components would be ideal since they’re path-aware, but they don’t support carryforward.

Describe the solution you'd like Allow automatic flag assignment based on file path or package name during upload, so monorepos can use carryforward without complex CI setups.

Describe alternatives you've considered

• Using Components (but they don’t support carryforward)
• Splitting CI into multiple upload steps (hard to maintain)

Additional context The users repo runs all package tests in one step and uploads once. Auto-flagging based on coverage file paths would simplify setup and improve maintainability.