Auto-fix JSON comments and trailing commas for HTTP request bodies

Add a per-request "Automatically Fix JSON" toggle (default: on) that strips
comments and trailing commas before sending HTTP requests. When disabled,
comments are sent as-is and the editor linter flags them as errors.

- New JsonBodyEditor component with settings dropdown and dismissible banner
- Configurable JSON linter (allowComments/allowTrailingCommas) via lintExtension prop
- strip_trailing_commas pass in Rust strip_json_comments pipeline
- Fix JSON formatter pulling standalone comments onto previous comma line
- Add get_bool_map helper, maybe_strip_json_comments, and related tests

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

src-web/lib/jsonComments.ts

@@ -0,0 +1,30 @@
+/**
+ * Simple heuristic to detect if a string likely contains JSON/JSONC comments.
+ * Checks for // and /* patterns that are NOT inside double-quoted strings.
+ * Used for UI hints only — doesn't need to be perfect.
+ */
+export function textLikelyContainsJsonComments(text: string): boolean {
+  let inString = false;
+  for (let i = 0; i < text.length; i++) {
+    const ch = text[i];
+    if (inString) {
+      if (ch === '"') {
+        inString = false;
+      } else if (ch === '\\') {
+        i++; // skip escaped char
+      }
+      continue;
+    }
+    if (ch === '"') {
+      inString = true;
+      continue;
+    }
+    if (ch === '/' && i + 1 < text.length) {
+      const next = text[i + 1];
+      if (next === '/' || next === '*') {
+        return true;
+      }
+    }
+  }
+  return false;
+}