proofshot.config.json should support project-level browser settings

proofshot.config.json should support project-level browser settings: a task in LegoFlow-SWE (Harbor dataset). Problem ProofShot currently inherits the user’s global ~/.agent-browser/config.json for all browser operations. This means personal browser settings (e.g., custom flags, executable paths…

The task

**Problem** ProofShot currently inherits the user’s global `~/.agent-browser/config.json` for all browser operations. This means personal browser settings (e.g., custom flags, executable paths, or alternate configurations) leak into project verification runs, leading to inconsistent behavior across machines and…

Part of Lego-X/LegoFlow-SWE.