docs: fix typo in README quickstart section (#123)

Changed `cd standard_agent` to `cd standard-agent` to match
the actual repository name (using hyphen instead of underscore).

Fixes #70

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: sahajshukla

README.md

@@ -42,7 +42,7 @@ We hope the community will benefit from *Standard Agent* in the following ways:
 ```bash
 # Clone and set up the project
 git clone <repository-url>
-cd standard_agent
+cd standard-agent
 
 # Install dependencies
 make install