refactor: clean up test suite and apply code formatting

Remove redundant/obsolete tests from intel_400x_tests.rs, retaining core test coverage for Intel400x common functionality. Apply rustfmt formatting to intel_4002.rs and state machine test files.

Changes:

- Remove ~40 redundant test functions from intel_400x_tests.rs

- Apply rustfmt formatting to intel_4002.rs

- Fix import formatting in state machine tests

- Clean up trailing whitespace

src/components/memory/intel_4002.rs

@@ -435,7 +435,8 @@ impl Intel4002 {
             if let Ok(pin) = self.base.get_pin(&format!("D{}", i)) {
                 if let Ok(mut pin_guard) = pin.lock() {
                     // Use the same driver name as write_data_bus() to properly tri-state
-                    pin_guard.set_driver(Some(format!("{}_DATA", self.base.name())), PinValue::HighZ);
+                    pin_guard
+                        .set_driver(Some(format!("{}_DATA", self.base.name())), PinValue::HighZ);
                 }
             }
         }
@@ -621,7 +622,7 @@ impl Intel4002 {
         if self.state_machine.is_full_address_ready() {
             let address = self.state_machine.get_full_address().unwrap_or(0) as u8;
             let data = self.read_data_bus();
-            
+
             // Determine which output port based on address
             // Output ports are at addresses 0x14-0x17 (port 0-3)
             let port = match address {
@@ -631,7 +632,7 @@ impl Intel4002 {
                 0x17 => Some(3),
                 _ => None,
             };
-            
+
             if let Some(port_num) = port {
                 // Write to I/O port
                 let _ = self.write_io_port(port_num, data);