fix: resolve CI/CD issues - remove unused dependencies and imports

- Remove unused thiserror dependency from Cargo.toml
- Remove unused imports (Text, Tabs, Widget, Event, KeyCode, KeyEventKind) from tui/mod.rs
- Remove unused imports (File, Write) from export/mod.rs
- Remove unused pub use ComplexityDistribution from core/analyzer.rs

techdebt-tracker-cli/tests/fixtures/sample.py

@@ -0,0 +1,94 @@
+# Python sample file with technical debt comments
+
+def calculate_average(numbers):
+    # TODO: Handle empty list case
+    return sum(numbers) / len(numbers)
+
+
+def process_user(user_data):
+    # FIXME: This may raise KeyError for missing fields
+    name = user_data['name']
+    email = user_data['email']
+    return {'name': name, 'email': email}
+
+
+def fetch_data_from_api(endpoint):
+    # HACK: Skip SSL verification for testing
+    import requests
+    response = requests.get(endpoint, verify=False)
+    # TODO: Add retry logic
+    return response.json()
+
+
+class DatabaseConnection:
+    def __init__(self, connection_string):
+        # FIXME: Connection string should be encrypted
+        self.connection_string = connection_string
+
+    def connect(self):
+        # BUG: Connection timeout not implemented
+        print("Connecting to database...")
+
+    def disconnect(self):
+        # NOTE: Pool cleanup happens automatically
+        print("Disconnecting...")
+
+
+def temp_workaround():
+    # TEMP: Quick fix for production issue
+    return None
+
+
+def old_implementation():
+    # REFACTOR: Use list comprehension instead
+    result = []
+    for i in range(10):
+        result.append(i * 2)
+    return result
+
+
+def validate_input(data):
+    # XXX: Critical security vulnerability!
+    # This eval is dangerous
+    return eval(data)  # nosec
+
+
+def complex_function():
+    # TODO: This function is too long, split it up
+    # TODO: Add type hints
+    # TODO: Add docstring
+    x = 1
+    y = 2
+    z = 3
+    a = 4
+    b = 5
+    return x + y + z + a + b
+
+
+class LegacyClass:
+    """This class needs refactoring."""
+    def __init__(self):
+        self._internal_state = None
+        # FIXME: Memory leak risk
+
+    def _old_method(self):
+        # NOTE: This is deprecated
+        pass
+
+    def new_method(self):
+        """Modern replacement for _old_method."""
+        pass
+
+
+# TODO: Add exception handling
+# TODO: Write docstrings for all public methods
+# TODO: Add unit tests
+
+def main():
+    data = [1, 2, 3, 4, 5]
+    avg = calculate_average(data)
+    print(f"Average: {avg}")
+
+
+if __name__ == "__main__":
+    main()