fix(forms): preserve regex quantifiers and use inline constraint errors

packages/compiler/src/codegen.ts

@@ -912,7 +912,7 @@ function renderNestedComponentInvocation(
 
       const compiledValue = wholeExpression
         ? `\${__wrnProp(${ctx.resolveExpr(wholeExpression)})}`
-        : compileAttrValue(attr.value, ctx);
+        : compileAttrValue(attr.value, ctx, attr.name === "pattern");
 
       const rendered = ` ${attr.name}="${compiledValue}"`;
 
@@ -2254,7 +2254,7 @@ function compileText(raw: string, ctx: CompCtx): string {
 }
 
 /** Compile an attribute value; `{expr}` is baked server-side (loop vars stay literal). */
-function compileAttrValue(raw: string, ctx: CompCtx): string {
+function compileAttrValue(raw: string, ctx: CompCtx, regexPattern = false): string {
   if (!raw.includes("{")) return escLit(attrEscape(raw));
   let out = "";
   let last = 0;
@@ -2263,7 +2263,9 @@ function compileAttrValue(raw: string, ctx: CompCtx): string {
   while ((m = INTERP_RE.exec(raw))) {
     out += escLit(attrEscape(raw.slice(last, m.index)));
     const expr = m[1]!.trim();
-    if (ctx.loopVars && exprRefsState(expr, ctx.loopVars)) {
+    if (regexPattern && /^\d+(?:,\d*)?$/.test(expr)) {
+      out += escLit(attrEscape(m[0])); // Regex quantifiers are not template expressions.
+    } else if (ctx.loopVars && exprRefsState(expr, ctx.loopVars)) {
       out += escLit(`{${expr}}`); // hydrated per-item by the list renderer
     } else {
       out += `\${__wrnAttr(${ctx.resolveExpr(expr)})}`;
@@ -2628,7 +2630,7 @@ function renderComponentNode(node: ViewNode, ctx: CompCtx): string {
       const compiledValue =
         isExplicitComponentMount && wholeExpression
           ? `\${__wrnProp(${elementContext.resolveExpr(wholeExpression)})}`
-          : compileAttrValue(a.value, elementContext);
+          : compileAttrValue(a.value, elementContext, a.name === "pattern");
 
       /*
        * A constraint attribute whose value is only known at render time (a