feat(agents): implement agent framework and CLI

tests/fixtures/complex-function.diff

@@ -0,0 +1,69 @@
+diff --git a/src/processor.py b/src/processor.py
+index 1234567..abcdefg 100644
+--- a/src/processor.py
++++ b/src/processor.py
+@@ -1,5 +1,65 @@
+ """Data processor module."""
+
+
++def process_data(data: dict, config: dict, options: dict | None = None) -> dict:
++    """Process data with many nested conditions."""
++    result = {}
++    options = options or {}
++
++    if data.get("type") == "A":
++        if config.get("mode") == "strict":
++            if options.get("validate"):
++                if data.get("value") > 100:
++                    if config.get("transform"):
++                        result["processed"] = data["value"] * 2
++                    else:
++                        result["processed"] = data["value"]
++                else:
++                    if options.get("default"):
++                        result["processed"] = options["default"]
++                    else:
++                        result["processed"] = 0
++            else:
++                result["processed"] = data.get("value", 0)
++        else:
++            result["processed"] = data.get("value", 0)
++    elif data.get("type") == "B":
++        if config.get("mode") == "strict":
++            if options.get("validate"):
++                if data.get("items"):
++                    result["processed"] = len(data["items"])
++                else:
++                    result["processed"] = 0
++            else:
++                result["processed"] = len(data.get("items", []))
++        else:
++            result["processed"] = len(data.get("items", []))
++    elif data.get("type") == "C":
++        if config.get("mode") == "strict":
++            if options.get("validate"):
++                if data.get("text"):
++                    result["processed"] = data["text"].upper()
++                else:
++                    result["processed"] = ""
++            else:
++                result["processed"] = data.get("text", "").upper()
++        else:
++            result["processed"] = data.get("text", "").upper()
++    else:
++        if config.get("fallback"):
++            result["processed"] = config["fallback"]
++        else:
++            result["processed"] = None
++
++    if options.get("timestamp"):
++        result["timestamp"] = options["timestamp"]
++    if options.get("source"):
++        result["source"] = options["source"]
++
++    return result
++
++
+ def simple_function(x: int) -> int:
+     """A simple function."""
+     return x * 2

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"

tests/fixtures/simple.diff

@@ -0,0 +1,16 @@
+diff --git a/src/utils.py b/src/utils.py
+index 1234567..abcdefg 100644
+--- a/src/utils.py
++++ b/src/utils.py
+@@ -1,5 +1,8 @@
+ """Utility functions."""
+
+
++def add(a: int, b: int) -> int:
++    """Add two numbers."""
++    return a + b
++
++
+ def subtract(a: int, b: int) -> int:
+     """Subtract two numbers."""
+     return a - b