branch wise monitoring in amplify, currently its at app level only

**Is your feature request related to a problem? Please describe.**
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]

**Describe the solution you'd like**
A clear and concise description of what you want to happen.

**Additional context**
Add any other context or screenshots about the feature request here.

The issue mentions AWS Amplify Hosting and branch-wise monitoring but provides no files, tests, entry points, or concrete solution. Start by clarifying the desired branch-level monitoring behavior and acceptance criteria; the work is done when those requirements are implemented and verified for individual branches.

Written by the indexing model from the issue text.