refactor: move task_fn into its own crate

benches/basic/scaling.rs

@@ -1,7 +1,8 @@
 //! DAG scaling benchmarks - how performance scales with task count
 
 use criterion::{BenchmarkId, Criterion};
-use dagx::{task_fn, DagRunner};
+use dagx::DagRunner;
+use dagx_test::task_fn;
 
 pub fn bench_dag_scaling(c: &mut Criterion) {
     let rt = tokio::runtime::Runtime::new().unwrap();

benches/comparisons/deep_chain.rs

@@ -13,7 +13,8 @@ pub fn bench_deep_chain(c: &mut Criterion) {
     group.bench_function("dagx", |b| {
         b.iter(|| {
             rt.block_on(async {
-                use dagx::{task_fn, DagRunner};
+                use dagx::DagRunner;
+                use dagx_test::task_fn;
 
                 let dag = DagRunner::new();
 

benches/comparisons/diamond_pattern.rs

@@ -13,7 +13,8 @@ pub fn bench_diamond_pattern(c: &mut Criterion) {
     group.bench_function("dagx", |b| {
         b.iter(|| {
             rt.block_on(async {
-                use dagx::{task_fn, DagRunner};
+                use dagx::DagRunner;
+                use dagx_test::task_fn;
 
                 let dag = DagRunner::new();
 

benches/comparisons/etl_pipeline.rs

@@ -12,7 +12,8 @@ pub fn bench_etl_pipeline(c: &mut Criterion) {
     group.bench_function("dagx", |b| {
         b.iter(|| {
             rt.block_on(async {
-                use dagx::{task_fn, DagRunner};
+                use dagx::DagRunner;
+                use dagx_test::task_fn;
 
                 let dag = DagRunner::new();
 

benches/comparisons/large_scale.rs

@@ -14,7 +14,8 @@ pub fn bench_large_scale(c: &mut Criterion) {
     group.bench_function("dagx", |b| {
         b.iter(|| {
             rt.block_on(async {
-                use dagx::{task_fn, DagRunner};
+                use dagx::DagRunner;
+                use dagx_test::task_fn;
 
                 let dag = DagRunner::new();
                 for i in 0..10_000 {

benches/comparisons/linear_pipeline.rs

@@ -12,7 +12,8 @@ pub fn bench_linear_pipeline(c: &mut Criterion) {
     group.bench_function("dagx", |b| {
         b.iter(|| {
             rt.block_on(async {
-                use dagx::{task_fn, DagRunner};
+                use dagx::DagRunner;
+                use dagx_test::task_fn;
 
                 let dag = DagRunner::new();
 

benches/comparisons/wide_fanout.rs

@@ -13,7 +13,8 @@ pub fn bench_wide_fanout(c: &mut Criterion) {
     group.bench_function("dagx", |b| {
         b.iter(|| {
             rt.block_on(async {
-                use dagx::{task_fn, DagRunner};
+                use dagx::DagRunner;
+                use dagx_test::task_fn;
 
                 let dag = DagRunner::new();
                 let source: TaskHandle<_> = dag.add_task(task_fn::<(), _, _>(|_: ()| 42)).into();

benches/patterns/breakdown.rs

@@ -1,7 +1,8 @@
 //! 10,000 task breakdown benchmarks - construction vs execution
 
 use criterion::{BatchSize, Criterion};
-use dagx::{task_fn, DagRunner};
+use dagx::DagRunner;
+use dagx_test::task_fn;
 
 pub fn bench_10k_breakdown(c: &mut Criterion) {
     let rt = tokio::runtime::Runtime::new().unwrap();

benches/patterns/diamond.rs

@@ -1,8 +1,8 @@
 //! Diamond pattern benchmarks (fan-out then fan-in)
 
 use criterion::Criterion;
-use dagx::{task_fn, DagRunner, TaskHandle};
-
+use dagx::{DagRunner, TaskHandle};
+use dagx_test::task_fn;
 pub fn bench_diamond(c: &mut Criterion) {
     let rt = tokio::runtime::Runtime::new().unwrap();
 

benches/patterns/fanout.rs

@@ -1,8 +1,8 @@
 //! Fan-out pattern benchmarks (1 → N dependencies)
 
 use criterion::Criterion;
-use dagx::{task_fn, DagRunner, TaskHandle};
-
+use dagx::{DagRunner, TaskHandle};
+use dagx_test::task_fn;
 pub fn bench_fanout(c: &mut Criterion) {
     let rt = tokio::runtime::Runtime::new().unwrap();
 

benches/realistic/etl.rs

@@ -1,8 +1,8 @@
 //! ETL (Extract, Transform, Load) pipeline benchmark
 
 use criterion::{BenchmarkId, Criterion};
-use dagx::{task_fn, DagRunner, TaskHandle};
-
+use dagx::{DagRunner, TaskHandle};
+use dagx_test::task_fn;
 pub fn bench_etl_pipeline(c: &mut Criterion) {
     let rt = tokio::runtime::Runtime::new().unwrap();
     let mut group = c.benchmark_group("etl_scaling");

benches/realistic/memory_efficiency.rs

@@ -1,8 +1,8 @@
 //! Memory efficiency benchmark with large data structures
 
 use criterion::{BenchmarkId, Criterion};
-use dagx::{task_fn, DagRunner, TaskHandle};
-
+use dagx::{DagRunner, TaskHandle};
+use dagx_test::task_fn;
 use std::hint::black_box;
 
 pub fn bench_memory_efficiency(c: &mut Criterion) {

benches/realistic/mixed.rs

@@ -1,8 +1,8 @@
 //! Mixed realistic patterns - fan-out, fan-in, and processing
 
 use criterion::Criterion;
-use dagx::{task_fn, DagRunner, TaskHandle};
-
+use dagx::{DagRunner, TaskHandle};
+use dagx_test::task_fn;
 pub fn bench_mixed_patterns(c: &mut Criterion) {
     let rt = tokio::runtime::Runtime::new().unwrap();