fix(core): type slot render payloads

Tighten typed Slot::render and KeyedSlot append/prepend/replace helpers so callers pass the generated slot payload type, keeping explicit html/text escape hatches for deliberate conversions.

req: codegen/002

req: typed_id/001

slhx-core/src/lib.rs

@@ -713,7 +713,10 @@ impl<T> Slot<T> {
         self.id
     }
 
-    pub fn render(self, value: impl ToString) -> Effect {
+    pub fn render(self, value: T) -> Effect
+    where
+        T: ToString,
+    {
         self.text(value)
     }
 
@@ -761,7 +764,10 @@ where
         self.id
     }
 
-    pub fn append(self, key: K, value: impl ToString) -> Effect {
+    pub fn append(self, key: K, value: T) -> Effect
+    where
+        T: ToString,
+    {
         Effect::Insert {
             target: ResourceRef::unscoped(self.id),
             key: key.to_string(),
@@ -769,7 +775,10 @@ where
         }
     }
 
-    pub fn prepend(self, key: K, value: impl ToString) -> Effect {
+    pub fn prepend(self, key: K, value: T) -> Effect
+    where
+        T: ToString,
+    {
         Effect::Prepend {
             target: ResourceRef::unscoped(self.id),
             key: key.to_string(),
@@ -777,7 +786,10 @@ where
         }
     }
 
-    pub fn replace(self, key: K, value: impl ToString) -> Effect {
+    pub fn replace(self, key: K, value: T) -> Effect
+    where
+        T: ToString,
+    {
         let key = key.to_string();
         Effect::Put {
             target: ResourceRef {