Fix renderComponentDOM: route render-only forms through renderDOM

The previous fix eagerly evaluated all kwarg expressions via sxEval,
which broke render-only forms (<>, raw!, HTML tags, ~components) that
only exist in the render pipeline. Now detect render expressions by
checking if the head symbol is an HTML/SVG tag, <>, raw!, or ~component,
and route those through renderDOM while data expressions still go
through sxEval for correct scope resolution.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

blog/models/content.py

@@ -118,7 +118,7 @@ class Post(Base):
         secondary="post_authors",
         primaryjoin="Post.id==post_authors.c.post_id",
         secondaryjoin="Author.id==post_authors.c.author_id",
-        back_populates="authors",
+        back_populates="posts",
         order_by="PostAuthor.sort_order",
     )
 

shared/static/scripts/sx.js

@@ -808,18 +808,32 @@
     return renderDOM(fn.body, local);
   }
 
+  /** True when the array expr is a render-only form (HTML tag, <>, raw!, ~comp). */
+  function _isRenderExpr(v) {
+    if (!Array.isArray(v) || !v.length) return false;
+    var h = v[0];
+    if (!isSym(h)) return false;
+    var n = h.name;
+    return !!(HTML_TAGS[n] || SVG_TAGS[n] || n === "<>" || n === "raw!" || n.charAt(0) === "~");
+  }
+
   function renderComponentDOM(comp, args, env) {
     var kwargs = {}, children = [];
     var i = 0;
     while (i < args.length) {
       if (isKw(args[i]) && i + 1 < args.length) {
-        // Keep kwarg values as AST — renderDOM will handle them when the
+        // Evaluate kwarg values eagerly in the caller's env so expressions
-        // component body references the param symbol.  Simple literals are
+        // like (get t "src") resolve while lambda params are still bound.
-        // eval'd so strings/numbers resolve immediately.
+        // Render-only forms (HTML tags, <>, ~comp) go through renderDOM instead.
         var v = args[i + 1];
-        kwargs[args[i].name] = (typeof v === "string" || typeof v === "number" ||
+        if (typeof v === "string" || typeof v === "number" ||
-          typeof v === "boolean" || isNil(v) || isKw(v))
+          typeof v === "boolean" || isNil(v)) {
-          ? v : (isSym(v) ? sxEval(v, env) : v);
+          kwargs[args[i].name] = v;
+        } else if (_isRenderExpr(v)) {
+          kwargs[args[i].name] = renderDOM(v, env);
+        } else {
+          kwargs[args[i].name] = sxEval(v, env);
+        }
         i += 2;
       } else {
         children.push(args[i]);