fix(hydroflow_lang)!: remove singleton persist insertion

Also enables singletons for `persist()` and ensures that only the
`'static` lifetime is used

hydroflow/tests/snapshots/surface_singleton__fold_cross@graphvis_dot.snap

@@ -1,6 +1,6 @@
 ---
 source: hydroflow/tests/surface_singleton.rs
-expression: "df.meta_graph().unwrap().to_dot(&Default::default())"
+expression: "df.meta_graph().unwrap().to_dot(& Default :: default())"
 ---
 digraph {
     node [fontname="Monaco,Menlo,Consolas,"Droid Sans Mono",Inconsolata,"Courier New",monospace", style=filled];
@@ -12,28 +12,26 @@ digraph {
     n5v1 [label="(n5v1) tee()", shape=house, fillcolor="#ffff88"]
     n6v1 [label="(n6v1) identity::<Max<_>>()", shape=invhouse, fillcolor="#88aaff"]
     n7v1 [label="(n7v1) cross_join()", shape=invhouse, fillcolor="#88aaff"]
-    n8v1 [label="(n8v1) persist::<'static>()", shape=invhouse, fillcolor="#88aaff"]
-    n9v1 [label="(n9v1) filter(|(value, max_of_stream2)| { value <= max_of_stream2.as_reveal_ref() })", shape=invhouse, fillcolor="#88aaff"]
-    n10v1 [label="(n10v1) map(|(x, _max)| (context.current_tick(), x))", shape=invhouse, fillcolor="#88aaff"]
-    n11v1 [label="(n11v1) for_each(|x| filter_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
-    n12v1 [label="(n12v1) map(|x: Max<_>| (context.current_tick(), x.into_reveal()))", shape=house, fillcolor="#ffff88"]
-    n13v1 [label="(n13v1) for_each(|x| max_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
+    n8v1 [label="(n8v1) filter(|(value, max_of_stream2)| { value <= max_of_stream2.as_reveal_ref() })", shape=invhouse, fillcolor="#88aaff"]
+    n9v1 [label="(n9v1) map(|(x, _max)| (context.current_tick(), x))", shape=invhouse, fillcolor="#88aaff"]
+    n10v1 [label="(n10v1) for_each(|x| filter_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
+    n11v1 [label="(n11v1) map(|x: Max<_>| (context.current_tick(), x.into_reveal()))", shape=house, fillcolor="#ffff88"]
+    n12v1 [label="(n12v1) for_each(|x| max_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
+    n13v1 [label="(n13v1) handoff", shape=parallelogram, fillcolor="#ddddff"]
     n14v1 [label="(n14v1) handoff", shape=parallelogram, fillcolor="#ddddff"]
-    n15v1 [label="(n15v1) handoff", shape=parallelogram, fillcolor="#ddddff"]
     n2v1 -> n3v1 [color=darkgreen, style=dashed]
     n4v1 -> n5v1 [color=darkgreen, style=bold]
-    n3v1 -> n14v1 [color=darkgreen, style=dashed]
+    n3v1 -> n13v1 [color=darkgreen, style=dashed]
     n1v1 -> n7v1 [label="0"]
     n6v1 -> n7v1 [label="1"]
-    n5v1 -> n15v1 [color=darkgreen, style=bold]
-    n10v1 -> n11v1
+    n5v1 -> n14v1 [color=darkgreen, style=bold]
     n9v1 -> n10v1
     n8v1 -> n9v1
     n7v1 -> n8v1
-    n12v1 -> n13v1 [color=darkgreen, style=bold]
-    n5v1 -> n12v1 [color=darkgreen, style=bold]
-    n14v1 -> n4v1 [color=red, style=dashed]
-    n15v1 -> n6v1 [color=darkgreen, style=bold]
+    n11v1 -> n12v1 [color=darkgreen, style=bold]
+    n5v1 -> n11v1 [color=darkgreen, style=bold]
+    n13v1 -> n4v1 [color=red, style=dashed]
+    n14v1 -> n6v1 [color=darkgreen, style=bold]
     subgraph "cluster n1v1" {
         fillcolor="#dddddd"
         style=filled
@@ -56,14 +54,12 @@ digraph {
         n8v1
         n9v1
         n10v1
-        n11v1
         subgraph "cluster_sg_2v1_var_filtered_stream2" {
             label="var filtered_stream2"
             n7v1
             n8v1
             n9v1
             n10v1
-            n11v1
         }
         subgraph "cluster_sg_2v1_var_stream1" {
             label="var stream1"
@@ -76,8 +72,8 @@ digraph {
         label = "sg_3v1\nstratum 0"
         n4v1
         n5v1
+        n11v1
         n12v1
-        n13v1
         subgraph "cluster_sg_3v1_var_max_of_stream2" {
             label="var max_of_stream2"
             n4v1

hydroflow/tests/snapshots/surface_singleton__fold_cross@graphvis_mermaid.snap

@@ -1,6 +1,6 @@
 ---
 source: hydroflow/tests/surface_singleton.rs
-expression: "df.meta_graph().unwrap().to_mermaid(&Default::default())"
+expression: "df.meta_graph().unwrap().to_mermaid(& Default :: default())"
 ---
 %%{init:{'theme':'base','themeVariables':{'clusterBkg':'#ddd','clusterBorder':'#888'}}}%%
 flowchart TD
@@ -15,28 +15,26 @@ linkStyle default stroke:#aaa
 5v1[/"(5v1) <code>tee()</code>"\]:::pushClass
 6v1[\"(6v1) <code>identity::&lt;Max&lt;_&gt;&gt;()</code>"/]:::pullClass
 7v1[\"(7v1) <code>cross_join()</code>"/]:::pullClass
-8v1[\"(8v1) <code>persist::&lt;'static&gt;()</code>"/]:::pullClass
-9v1[\"(9v1) <code>filter(|(value, max_of_stream2)| { value &lt;= max_of_stream2.as_reveal_ref() })</code>"/]:::pullClass
-10v1[\"(10v1) <code>map(|(x, _max)| (context.current_tick(), x))</code>"/]:::pullClass
-11v1[/"(11v1) <code>for_each(|x| filter_send.send(x).unwrap())</code>"\]:::pushClass
-12v1[/"(12v1) <code>map(|x: Max&lt;_&gt;| (context.current_tick(), x.into_reveal()))</code>"\]:::pushClass
-13v1[/"(13v1) <code>for_each(|x| max_send.send(x).unwrap())</code>"\]:::pushClass
+8v1[\"(8v1) <code>filter(|(value, max_of_stream2)| { value &lt;= max_of_stream2.as_reveal_ref() })</code>"/]:::pullClass
+9v1[\"(9v1) <code>map(|(x, _max)| (context.current_tick(), x))</code>"/]:::pullClass
+10v1[/"(10v1) <code>for_each(|x| filter_send.send(x).unwrap())</code>"\]:::pushClass
+11v1[/"(11v1) <code>map(|x: Max&lt;_&gt;| (context.current_tick(), x.into_reveal()))</code>"\]:::pushClass
+12v1[/"(12v1) <code>for_each(|x| max_send.send(x).unwrap())</code>"\]:::pushClass
+13v1["(13v1) <code>handoff</code>"]:::otherClass
 14v1["(14v1) <code>handoff</code>"]:::otherClass
-15v1["(15v1) <code>handoff</code>"]:::otherClass
 2v1-.->3v1; linkStyle 0 stroke:#060
 4v1==>5v1; linkStyle 1 stroke:#060
-3v1-.->14v1; linkStyle 2 stroke:#060
+3v1-.->13v1; linkStyle 2 stroke:#060
 1v1-->|0|7v1
 6v1-->|1|7v1
-5v1==>15v1; linkStyle 5 stroke:#060
-10v1-->11v1
+5v1==>14v1; linkStyle 5 stroke:#060
 9v1-->10v1
 8v1-->9v1
 7v1-->8v1
-12v1==>13v1; linkStyle 10 stroke:#060
-5v1==>12v1; linkStyle 11 stroke:#060
-14v1-.->4v1; linkStyle 12 stroke:#060
-15v1==>6v1; linkStyle 13 stroke:#060
+11v1==>12v1; linkStyle 9 stroke:#060
+5v1==>11v1; linkStyle 10 stroke:#060
+13v1-.->4v1; linkStyle 11 stroke:#060
+14v1==>6v1; linkStyle 12 stroke:#060
 subgraph sg_1v1 ["sg_1v1 stratum 0"]
     2v1
     3v1
@@ -52,13 +50,11 @@ subgraph sg_2v1 ["sg_2v1 stratum 0"]
     8v1
     9v1
     10v1
-    11v1
     subgraph sg_2v1_var_filtered_stream2 ["var <tt>filtered_stream2</tt>"]
         7v1
         8v1
         9v1
         10v1
-        11v1
     end
     subgraph sg_2v1_var_stream1 ["var <tt>stream1</tt>"]
         1v1
@@ -67,8 +63,8 @@ end
 subgraph sg_3v1 ["sg_3v1 stratum 0"]
     4v1
     5v1
+    11v1
     12v1
-    13v1
     subgraph sg_3v1_var_max_of_stream2 ["var <tt>max_of_stream2</tt>"]
         4v1
         5v1

hydroflow/tests/snapshots/surface_singleton__fold_singleton@graphvis_dot.snap

@@ -1,29 +1,27 @@
 ---
 source: hydroflow/tests/surface_singleton.rs
-expression: "df.meta_graph().unwrap().to_dot(&Default::default())"
+expression: "df.meta_graph().unwrap().to_dot(& Default :: default())"
 ---
 digraph {
     node [fontname="Monaco,Menlo,Consolas,"Droid Sans Mono",Inconsolata,"Courier New",monospace", style=filled];
     edge [fontname="Monaco,Menlo,Consolas,"Droid Sans Mono",Inconsolata,"Courier New",monospace"];
     n1v1 [label="(n1v1) source_iter(1..=10)", shape=invhouse, fillcolor="#88aaff"]
     n2v1 [label="(n2v1) source_iter(3..=5)", shape=invhouse, fillcolor="#88aaff"]
     n3v1 [label="(n3v1) fold(|| 0, |a, b| *a = std::cmp::max(*a, b))", shape=invhouse, fillcolor="#88aaff"]
-    n4v1 [label="(n4v1) persist::<'static>()", shape=invhouse, fillcolor="#88aaff"]
-    n5v1 [label="(n5v1) filter(|&value| { value <= max_of_stream2 })", shape=invhouse, fillcolor="#88aaff"]
-    n6v1 [label="(n6v1) map(|x| (context.current_tick(), x))", shape=invhouse, fillcolor="#88aaff"]
-    n7v1 [label="(n7v1) for_each(|x| filter_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
-    n8v1 [label="(n8v1) map(|x| (context.current_tick(), x))", shape=invhouse, fillcolor="#88aaff"]
-    n9v1 [label="(n9v1) for_each(|x| max_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
-    n10v1 [label="(n10v1) handoff", shape=parallelogram, fillcolor="#ddddff"]
-    n2v1 -> n10v1
-    n6v1 -> n7v1
+    n4v1 [label="(n4v1) filter(|&value| { value <= max_of_stream2 })", shape=invhouse, fillcolor="#88aaff"]
+    n5v1 [label="(n5v1) map(|x| (context.current_tick(), x))", shape=invhouse, fillcolor="#88aaff"]
+    n6v1 [label="(n6v1) for_each(|x| filter_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
+    n7v1 [label="(n7v1) map(|x| (context.current_tick(), x))", shape=invhouse, fillcolor="#88aaff"]
+    n8v1 [label="(n8v1) for_each(|x| max_send.send(x).unwrap())", shape=house, fillcolor="#ffff88"]
+    n9v1 [label="(n9v1) handoff", shape=parallelogram, fillcolor="#ddddff"]
+    n2v1 -> n9v1
     n5v1 -> n6v1
     n4v1 -> n5v1
     n1v1 -> n4v1
-    n8v1 -> n9v1
-    n3v1 -> n8v1
-    n10v1 -> n3v1 [color=red]
-    n3v1 -> n5v1 [color=red]
+    n7v1 -> n8v1
+    n3v1 -> n7v1
+    n9v1 -> n3v1 [color=red]
+    n3v1 -> n4v1 [color=red]
     subgraph "cluster n1v1" {
         fillcolor="#dddddd"
         style=filled
@@ -42,13 +40,11 @@ digraph {
         n4v1
         n5v1
         n6v1
-        n7v1
         subgraph "cluster_sg_2v1_var_filtered_stream1" {
             label="var filtered_stream1"
             n4v1
             n5v1
             n6v1
-            n7v1
         }
         subgraph "cluster_sg_2v1_var_stream1" {
             label="var stream1"
@@ -60,8 +56,8 @@ digraph {
         style=filled
         label = "sg_3v1\nstratum 1"
         n3v1
+        n7v1
         n8v1
-        n9v1
         subgraph "cluster_sg_3v1_var_max_of_stream2" {
             label="var max_of_stream2"
             n3v1

hydroflow/tests/snapshots/surface_singleton__fold_singleton@graphvis_mermaid.snap

@@ -1,6 +1,6 @@
 ---
 source: hydroflow/tests/surface_singleton.rs
-expression: "df.meta_graph().unwrap().to_mermaid(&Default::default())"
+expression: "df.meta_graph().unwrap().to_mermaid(& Default :: default())"
 ---
 %%{init:{'theme':'base','themeVariables':{'clusterBkg':'#ddd','clusterBorder':'#888'}}}%%
 flowchart TD
@@ -11,22 +11,20 @@ linkStyle default stroke:#aaa
 1v1[\"(1v1) <code>source_iter(1..=10)</code>"/]:::pullClass
 2v1[\"(2v1) <code>source_iter(3..=5)</code>"/]:::pullClass
 3v1[\"(3v1) <code>fold(|| 0, |a, b| *a = std::cmp::max(*a, b))</code>"/]:::pullClass
-4v1[\"(4v1) <code>persist::&lt;'static&gt;()</code>"/]:::pullClass
-5v1[\"(5v1) <code>filter(|&amp;value| { value &lt;= max_of_stream2 })</code>"/]:::pullClass
-6v1[\"(6v1) <code>map(|x| (context.current_tick(), x))</code>"/]:::pullClass
-7v1[/"(7v1) <code>for_each(|x| filter_send.send(x).unwrap())</code>"\]:::pushClass
-8v1[\"(8v1) <code>map(|x| (context.current_tick(), x))</code>"/]:::pullClass
-9v1[/"(9v1) <code>for_each(|x| max_send.send(x).unwrap())</code>"\]:::pushClass
-10v1["(10v1) <code>handoff</code>"]:::otherClass
-2v1-->10v1
-6v1-->7v1
+4v1[\"(4v1) <code>filter(|&amp;value| { value &lt;= max_of_stream2 })</code>"/]:::pullClass
+5v1[\"(5v1) <code>map(|x| (context.current_tick(), x))</code>"/]:::pullClass
+6v1[/"(6v1) <code>for_each(|x| filter_send.send(x).unwrap())</code>"\]:::pushClass
+7v1[\"(7v1) <code>map(|x| (context.current_tick(), x))</code>"/]:::pullClass
+8v1[/"(8v1) <code>for_each(|x| max_send.send(x).unwrap())</code>"\]:::pushClass
+9v1["(9v1) <code>handoff</code>"]:::otherClass
+2v1-->9v1
 5v1-->6v1
 4v1-->5v1
 1v1-->4v1
-8v1-->9v1
-3v1-->8v1
-10v1--x3v1; linkStyle 7 stroke:red
-3v1--x5v1; linkStyle 8 stroke:red
+7v1-->8v1
+3v1-->7v1
+9v1--x3v1; linkStyle 6 stroke:red
+3v1--x4v1; linkStyle 7 stroke:red
 subgraph sg_1v1 ["sg_1v1 stratum 0"]
     2v1
     subgraph sg_1v1_var_stream2 ["var <tt>stream2</tt>"]
@@ -38,21 +36,19 @@ subgraph sg_2v1 ["sg_2v1 stratum 2"]
     4v1
     5v1
     6v1
-    7v1
     subgraph sg_2v1_var_filtered_stream1 ["var <tt>filtered_stream1</tt>"]
         4v1
         5v1
         6v1
-        7v1
     end
     subgraph sg_2v1_var_stream1 ["var <tt>stream1</tt>"]
         1v1
     end
 end
 subgraph sg_3v1 ["sg_3v1 stratum 1"]
     3v1
+    7v1
     8v1
-    9v1
     subgraph sg_3v1_var_max_of_stream2 ["var <tt>max_of_stream2</tt>"]
         3v1
     end