feat(agents): implement agent framework and CLI

tests/fixtures/security-issue.diff

@@ -0,0 +1,31 @@
+diff --git a/src/auth.py b/src/auth.py
+index 1234567..abcdefg 100644
+--- a/src/auth.py
++++ b/src/auth.py
+@@ -1,10 +1,25 @@
+ """Authentication module."""
+
+ import sqlite3
++import os
+
+
+ def get_user(username: str) -> dict | None:
+     """Get user from database."""
+     conn = sqlite3.connect("users.db")
+     cursor = conn.cursor()
+-    cursor.execute("SELECT * FROM users WHERE username = ?", (username,))
++    # FIXME: this is vulnerable to SQL injection
++    query = "SELECT * FROM users WHERE username = '" + username + "'"
++    cursor.execute(query)
+     return cursor.fetchone()
++
++
++def run_command(cmd: str) -> str:
++    """Run a shell command."""
++    # Command injection vulnerability
++    return os.popen(cmd).read()
++
++
++# Hardcoded credentials
++API_KEY = "sk-1234567890abcdef"
++DB_PASSWORD = "admin123"