feat: Add Extend and FromIterator traits to ZyntaxArray

- Implement Extend<T> for ZyntaxArray<T> to append from iterators
- Implement FromIterator<T> for ZyntaxArray<T> for collect() support
- Fix async_runtime_tests.rs for PromiseState::Cancelled variant
- Update INTEGRATION_PLAN.md to mark collection interop as complete

Author: darmie

crates/zyntax_embed/src/array.rs

@@ -380,6 +380,25 @@ impl<'a, T: Copy> IntoIterator for &'a mut ZyntaxArray<T> {
 unsafe impl<T: Copy + Send> Send for ZyntaxArray<T> {}
 unsafe impl<T: Copy + Sync> Sync for ZyntaxArray<T> {}
 
+impl<T: Copy> Extend<T> for ZyntaxArray<T> {
+    fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
+        for item in iter {
+            self.push(item);
+        }
+    }
+}
+
+impl<T: Copy> std::iter::FromIterator<T> for ZyntaxArray<T> {
+    fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
+        let iter = iter.into_iter();
+        let (lower, upper) = iter.size_hint();
+        let capacity = upper.unwrap_or(lower).max(8);
+        let mut arr = Self::with_capacity(capacity);
+        arr.extend(iter);
+        arr
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -459,4 +478,24 @@ mod tests {
         arr[1] = 42;
         assert_eq!(arr.as_slice(), &[1, 42, 3]);
     }
+
+    #[test]
+    fn test_extend() {
+        let mut arr: ZyntaxArray<i32> = [1, 2].into();
+        arr.extend([3, 4, 5]);
+        assert_eq!(arr.as_slice(), &[1, 2, 3, 4, 5]);
+    }
+
+    #[test]
+    fn test_from_iterator() {
+        let arr: ZyntaxArray<i32> = (0..5).collect();
+        assert_eq!(arr.as_slice(), &[0, 1, 2, 3, 4]);
+    }
+
+    #[test]
+    fn test_collect_after_map() {
+        let arr: ZyntaxArray<i32> = [1, 2, 3].into();
+        let doubled: ZyntaxArray<i32> = arr.as_slice().iter().map(|x| x * 2).collect();
+        assert_eq!(doubled.as_slice(), &[2, 4, 6]);
+    }
 }

crates/zyntax_embed/tests/async_runtime_tests.rs

@@ -1095,6 +1095,9 @@ async fn compute_value(x: i32) i32 {
                 PromiseState::Failed(err) => {
                     panic!("Async function failed: {}", err);
                 }
+                PromiseState::Cancelled => {
+                    panic!("Async function was cancelled");
+                }
                 PromiseState::Pending => {
                     if polls > 10 {
                         panic!("Too many polls");

docs/INTEGRATION_PLAN.md

@@ -265,12 +265,12 @@ fn test_array_push() {
 |------|--------|--------|----------|--------|
 | Type tags in zrtl_macros | High | Medium | P0 | ✅ Done (in zrtl crate) |
 | DynamicBox in zrtl_macros | High | Medium | P0 | ✅ Done (in zrtl crate) |
-| TypeRegistry in embed | High | Low | P0 | 🔲 Pending |
+| TypeRegistry in embed | High | Low | P0 | ✅ Done (re-exported) |
 | ZRTL plugin loading | High | Medium | P1 | ✅ Done |
 | Variadic function calls | High | High | P1 | ✅ Done (0-8 args) |
 | GenericBox support | Medium | Medium | P1 | ✅ Done (in zrtl crate) |
 | Iterator traits | Medium | Medium | P2 | ✅ Done |
-| Collection interop | Medium | Low | P2 | 🔲 Pending |
+| Collection interop | Medium | Low | P2 | ✅ Done |
 | Async state machine | Medium | High | P2 | ✅ Done |
 | Cancellation | Low | Medium | P3 | ✅ Done |
 | Promise combinators | Low | Low | P3 | ✅ Done |
@@ -286,7 +286,7 @@ fn test_array_push() {
 1. ✅ Add `TypeCategory`, `TypeFlags`, `TypeTag` to `zrtl` crate
 2. ✅ Add `DynamicBox` struct and accessors to `zrtl` crate
 3. ✅ Add `#[derive(ZrtlType)]` macro to `zrtl_macros`
-4. 🔲 Re-export `TypeRegistry` in `zyntax_embed`
+4. ✅ Re-export `TypeRegistry` in `zyntax_embed`
 
 ### Sprint 2: Runtime Integration ✅ COMPLETE
 
@@ -298,7 +298,7 @@ fn test_array_push() {
 
 1. ✅ Add `ZrtlIterable` and `ZrtlIterator` traits
 2. ✅ Implement for `ZyntaxArray` and `ZyntaxString`
-3. 🔲 Add collection conversion helpers (partial - basic From/Into impls exist)
+3. ✅ Add collection conversion helpers (Extend, FromIterator, From, Into)
 
 ### Sprint 4: Async & Polish ✅ COMPLETE