feat: add Chmod tool supporting a+x and a-x

[ezyang]

Stack from ghstack (oldest at bottom):

• -> feat: add Chmod tool supporting a+x and a-x #200

Add a tool Chmod which runs chmod on a file. Unlike standard chmod, we will only support a+x and a-x, because these are the only bits that git knows how to track.

f5bdd1b  (Base revision)
2a4c46d  Create chmod.py tool implementation
aecccaf  Add chmod to __init__.py exports
978c820  Add Chmod tool to system prompt in init_project.py
c980c91  Add Chmod to the Summary section in init_project.py
ce2bed8  Add mode parameter to the Summary section in init_project.py
c2247ea  Create end-to-end test for the Chmod tool
b2c432e  Add chmod import to main.py
7c7b51e  Add mode parameter to codemcp function signature
860272d  Add Chmod to expected_params dictionary
9a359e1  Add mode to provided_params dictionary
45aa5cc  Add Chmod subtool handler implementation
d5de573  Auto-commit format changes
90b87ba  Auto-commit lint changes
10e36c2  Add init_git_repo helper function to testing.py
630cf2b  Add __all__ list with init_git_repo in testing.py
b9445c4  Add pytest_asyncio import to test_chmod.py
4d1f672  Add pytest.mark.asyncio decorator to first test function
b726f97  Add pytest.mark.asyncio decorator to second test function
f40366f  Remove pytest_asyncio import
HEAD     Convert chmod test to use MCPEndToEndTestCase

codemcp-id: 208-feat-add-chmod-tool-supporting-a-x-and-a-x