Fix clippy warnings and formatting issues for CI

- Fix unused variables in ringkernel-ir tests (prefix with _)
- Replace approx PI constants (3.14) with non-PI values (3.125)
- Fix let_unit_value warnings by using assert_eq!
- Replace vec! with array literal for fixed-size buffer
- Remove needless borrow in Arc::ptr_eq call
- Use is_empty() instead of len() > 0
- Use iterator pattern instead of range loop
- Apply cargo fmt to profile.rs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: mivertowski

crates/ringkernel-cli/src/commands/profile.rs

@@ -196,8 +196,7 @@ pub async fn execute(
 
     // Check if kernel file exists (for file-based profiling)
     let kernel_path = Path::new(kernel);
-    let is_file_based =
-        kernel_path.exists() && kernel_path.extension().is_some_and(|e| e == "rs");
+    let is_file_based = kernel_path.exists() && kernel_path.extension().is_some_and(|e| e == "rs");
 
     let result = if is_file_based {
         profile_kernel_file(&config).await?

crates/ringkernel-core/src/checkpoint.rs

@@ -1174,10 +1174,10 @@ mod tests {
     #[test]
     fn test_checkpoint_validation() {
         // Test invalid magic
-        let mut bytes = vec![0u8; 64];
+        let mut bytes = [0u8; 64];
         bytes[0..8].copy_from_slice(&0u64.to_le_bytes()); // Wrong magic
 
-        let header = CheckpointHeader::from_bytes(bytes[0..64].try_into().unwrap());
+        let header = CheckpointHeader::from_bytes(&bytes);
         assert!(header.validate().is_err());
     }
 

crates/ringkernel-core/src/multi_gpu.rs

@@ -2939,7 +2939,7 @@ mod tests {
         let migrator = KernelMigrator::with_storage(coord.clone(), storage);
 
         // Verify we can access the coordinator
-        assert!(Arc::ptr_eq(&migrator.coordinator(), &coord));
+        assert!(Arc::ptr_eq(migrator.coordinator(), &coord));
     }
 
     #[test]

crates/ringkernel-core/src/runtime_context.rs

@@ -1443,7 +1443,7 @@ mod tests {
             metrics.is_empty()
                 || metrics.contains('#')
                 || metrics.contains('\n')
-                || metrics.len() > 0
+                || !metrics.is_empty()
         );
     }
 

crates/ringkernel-core/src/state.rs

@@ -545,10 +545,12 @@ mod tests {
     fn test_embedded_state_size_check() {
         // This should compile - TestState is exactly 24 bytes
         assert_eq!(std::mem::size_of::<TestState>(), 24);
-        let _ = <TestState as EmbeddedStateSize>::SIZE_CHECK;
+        // Force compile-time size check evaluation
+        assert_eq!(<TestState as EmbeddedStateSize>::SIZE_CHECK, ());
 
         // SmallState is smaller - also OK
         assert!(std::mem::size_of::<SmallState>() <= CONTROL_BLOCK_STATE_SIZE);
-        let _ = <SmallState as EmbeddedStateSize>::SIZE_CHECK;
+        // Force compile-time size check evaluation
+        assert_eq!(<SmallState as EmbeddedStateSize>::SIZE_CHECK, ());
     }
 }

crates/ringkernel-cpu/src/mock.rs

@@ -651,11 +651,11 @@ mod tests {
     fn test_mock_shared_memory() {
         let shmem = MockSharedMemory::new(1024);
 
-        shmem.write::<f32>(0, 3.14);
-        shmem.write::<f32>(4, 2.71);
+        shmem.write::<f32>(0, 3.125);
+        shmem.write::<f32>(4, 2.75);
 
-        assert!((shmem.read::<f32>(0) - 3.14).abs() < 0.001);
-        assert!((shmem.read::<f32>(4) - 2.71).abs() < 0.001);
+        assert!((shmem.read::<f32>(0) - 3.125).abs() < 0.001);
+        assert!((shmem.read::<f32>(4) - 2.75).abs() < 0.001);
 
         shmem.write_slice::<u32>(100, &[1, 2, 3, 4]);
         let slice = shmem.as_slice::<u32>(100, 4);

crates/ringkernel-graph/src/algorithms/bfs.rs

@@ -258,8 +258,8 @@ mod tests {
         let distances = bfs_sequential(&adj, &[NodeId(0)]).unwrap();
 
         assert_eq!(distances[0], Distance::new(0));
-        for i in 1..5 {
-            assert_eq!(distances[i], Distance::new(1));
+        for d in distances.iter().take(5).skip(1) {
+            assert_eq!(*d, Distance::new(1));
         }
     }
 

crates/ringkernel-ir/src/builder.rs

@@ -571,7 +571,7 @@ mod tests {
         let x = builder.parameter("x", IrType::ptr(IrType::F32));
         let y = builder.parameter("y", IrType::ptr(IrType::F32));
 
-        let idx = builder.thread_id(Dimension::X);
+        let _idx = builder.thread_id(Dimension::X);
         let x_val = builder.load(x);
         let y_val = builder.load(y);
         let result = builder.add(x_val, y_val);
@@ -588,7 +588,7 @@ mod tests {
         let mut builder = IrBuilder::new("test");
 
         let a = builder.const_i32(42);
-        let b = builder.const_f32(3.14);
+        let b = builder.const_f32(3.125);
         let c = builder.const_bool(true);
 
         let module = builder.build();

crates/ringkernel-ir/src/lower_wgsl.rs

@@ -846,7 +846,7 @@ mod tests {
     fn test_lower_with_subgroups() {
         let mut builder = IrBuilder::new("subgroup");
 
-        let val = builder.const_bool(true);
+        let _val = builder.const_bool(true);
         // WarpVote requires subgroups capability
 
         builder.ret();

crates/ringkernel-ir/src/nodes.rs

@@ -538,7 +538,7 @@ mod tests {
     #[test]
     fn test_constant_ir_type() {
         assert_eq!(ConstantValue::I32(42).ir_type(), IrType::I32);
-        assert_eq!(ConstantValue::F32(3.14).ir_type(), IrType::F32);
+        assert_eq!(ConstantValue::F32(3.125).ir_type(), IrType::F32);
         assert_eq!(ConstantValue::Bool(true).ir_type(), IrType::BOOL);
     }