chore: fit the loop-locals fix within the production gate

Three things the gate caught that the test suite could not.

The runtime size budget: writing `data-wrn-loop-locals` on client-rendered
loop items pushed reactive-runtime.ts to 51,603 against a 51,400 budget that
had only 125 bytes of headroom. Trimmed the encoder to the
btoa/encodeURIComponent idiom, recovering 65 bytes and leaving the smallest
form that still handles non-ASCII, then raised the budget to 51,600 with the
reason recorded in the file's own convention -- the remaining 263 bytes buy a
correctness fix, not a feature.

The VS Code extension bundles its own copy of the compiler, so the syntax and
compiler fixes made it stale. Rebuilt.

And a bug in the new test: `\{` inside a template literal is an unnecessary
escape, so the "brace inside a regex" case was testing an unescaped brace.
`\{` tests the case it was written for.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

editors/vscode/src/language-server.cjs

@@ -1,5 +1,5 @@
 #!/usr/bin/env node
-// WRN editor language server source hash: e55270eb33d7722a82d13d3a79097fea77eca69612aeba104e9cbdd8fc67e8c6
+// WRN editor language server source hash: cea070c2eebb5339c7b48f4200d34e51f2adb16eba4d6d3f92e5040081c5b079
 // WRN editor language server generator hash: f593a44aaf05495b789ce7a3086bee1eebb951b884d41c0e017bbcfe5f547e72
 // @bun @bun-cjs
 (function(exports, require, module, __filename, __dirname) {var __create = Object.create;
@@ -169671,6 +169671,64 @@ var isWs = (c) => c === " " || c === "\t" || c === `
 ` || c === "\r";
 var isIdentStart = (c) => /[A-Za-z_]/.test(c);
 var isIdentPart = (c) => /[A-Za-z0-9_]/.test(c);
+var REGEX_PRECEDING_KEYWORDS = new Set([
+  "return",
+  "typeof",
+  "instanceof",
+  "in",
+  "of",
+  "new",
+  "delete",
+  "void",
+  "do",
+  "else",
+  "yield",
+  "await",
+  "case"
+]);
+function opensRegex(src, i) {
+  let j = i - 1;
+  while (j >= 0 && (src[j] === " " || src[j] === "\t" || src[j] === "\r" || src[j] === `
+`))
+    j--;
+  if (j < 0)
+    return true;
+  const prev = src[j];
+  if (/[A-Za-z0-9_$]/.test(prev)) {
+    let k = j;
+    while (k >= 0 && /[A-Za-z0-9_$]/.test(src[k]))
+      k--;
+    return REGEX_PRECEDING_KEYWORDS.has(src.slice(k + 1, j + 1));
+  }
+  return prev !== ")" && prev !== "]" && prev !== "." && prev !== '"' && prev !== "'" && prev !== "`";
+}
+function skipRegex(src, i) {
+  let j = i + 1;
+  let inClass = false;
+  while (j < src.length) {
+    const c = src[j];
+    if (c === `
+`)
+      return null;
+    if (c === "\\") {
+      j += 2;
+      continue;
+    }
+    if (inClass) {
+      if (c === "]")
+        inClass = false;
+    } else if (c === "[") {
+      inClass = true;
+    } else if (c === "/") {
+      j++;
+      while (j < src.length && /[a-z]/.test(src[j]))
+        j++;
+      return j;
+    }
+    j++;
+  }
+  return null;
+}
 function skipLiteralOrComment(src, i, atLineStart) {
   const c = src[i];
   if (c === "/" && src[i + 1] === "*") {
@@ -169695,6 +169753,9 @@ function skipLiteralOrComment(src, i, atLineStart) {
     }
     return src.length;
   }
+  if (c === "/" && opensRegex(src, i)) {
+    return skipRegex(src, i);
+  }
   return null;
 }
 
@@ -169704,7 +169765,7 @@ class Lexer {
   constructor(src) {
     this.src = src;
   }
-  skipTrivia() {
+  skipWhitespaceAndLineComments() {
     const { src } = this;
     while (this.pos < src.length) {
       const c = src[this.pos];
@@ -169721,8 +169782,20 @@ class Lexer {
       break;
     }
   }
+  skipTrivia() {
+    const { src } = this;
+    while (this.pos < src.length) {
+      this.skipWhitespaceAndLineComments();
+      if (src[this.pos] === "/" && src[this.pos + 1] === "*") {
+        const close = src.indexOf("*/", this.pos + 2);
+        this.pos = close === -1 ? src.length : close + 2;
+        continue;
+      }
+      break;
+    }
+  }
   startsWithBlockComment() {
-    this.skipTrivia();
+    this.skipWhitespaceAndLineComments();
     return this.src[this.pos] === "/" && this.src[this.pos + 1] === "*";
   }
   next() {