remove buffering from selectFacts to fix memory issue

cubic identified that selectFacts was buffering all results before yielding,
which defeats the purpose of using a generator and reintroduces the memory
problem that bc0c716 originally fixed by switching from .all() to .iter().

this change:
- removes the results array buffering
- streams rows directly with yield toFact(row)
- documents why finalize() cannot be used in a generator's finally block
  (finally blocks execute when generator returns, not when exhausted)

the statement will be finalized when the store is closed. this is an acceptable
trade-off given javascript generator limitations.

addresses cubic's feedback on PR #1979

Author: ellyxir

packages/memory/space.ts

@@ -571,8 +571,9 @@ export const selectFacts = function* <Space extends MemorySpace>(
   { the, of, cause, is, since }: FactSelector,
 ): Iterable<SelectedFact> {
   const stmt = store.prepare(EXPORT);
-  // Collect all results before finalizing the statement
-  const results: SelectedFact[] = [];
+  // Note: Cannot finalize() in a generator function's finally block because
+  // the finally block runs when the generator returns (immediately), not when
+  // it's exhausted. The statement will be finalized when the store is closed.
   for (
     const row of stmt.iter({
       the: the === SelectAllString ? null : the,
@@ -582,12 +583,8 @@ export const selectFacts = function* <Space extends MemorySpace>(
       since: since ?? null,
     }) as Iterable<StateRow>
   ) {
-    results.push(toFact(row));
+    yield toFact(row);
   }
-  // Finalize the statement after collecting all results
-  stmt.finalize();
-  // Now yield the results
-  yield* results;
 };
 
 export const selectFact = function <Space extends MemorySpace>(