fix make test compatibility on windows

[sundaram2021]

Description

Fix make test (and all other make targets) failing on Windows when using Git Bash. uv installs itself to ~/.local/bin, which Git Bash does not include in PATH by default, causing every uv run command to fail with 'uv' is not recognized.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)

Related Issues

Fixes #6270

Changes Made

• Prepend ~/.local/bin to PATH in the Makefile so uv is discoverable by Git Bash on Windows
• Removed the previous over-engineered OS detection block (ifeq ($(OS),Windows_NT)) that introduced cd /d — a cmd.exe-only flag that broke Git Bash
• Restored plain cd for all targets, which works correctly across Git Bash, macOS, and Linux

Testing

Describe the tests you ran to verify your changes:

• Unit tests pass (cd core && pytest tests/)
• Lint passes (cd core && ruff check .)
• Manual testing performed — ran make test successfully in Git Bash on Windows after the fix; confirmed the previous 'uv' is not recognized error is gone

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Screenshots (if applicable)

Before: make test fails with 'uv' is not recognized as an internal or external command

After: make test runs all pytest suites successfully in powershell on Windows.

[sundaram2021]

please look into this PR and let me know if there any changes needed
cc: @bryanadenhq

[sundaram2021]

hey @Hundao ...can you please look into it ...really a small pr but really important one .
let me know if any changes needed , thanks