[compiler][playground] Formatting changes to pass tabs

Summary: Compiler pass tabs are bolded when their contents have changed from previous passes; but currently the HIR and JS tabs are unbolded. Conceptually they should be, if HIR is "changed" from the source code and JS is "changed" from the last IR phase.

In addition, the "show diff" option doesn't make a ton of sense for tabs that either aren't part of the pipeline (EnvironmentConfig) or (maybe more controversially, but imo) passes where the IR representation has changed since the last pass (BuildReactiveFunctions). This diff drops the button from those tabs.

[ghstack-poisoned]

compiler/apps/playground/components/Editor/Output.tsx

@@ -99,13 +99,14 @@ async function tabify(source: string, compilerOutput: CompilerOutput) {
     }
   }
   let lastPassOutput: string | null = null;
+  let nonDiffPasses = ["HIR", "BuildReactiveFunction", "EnvironmentConfig"];
   for (const [passName, text] of concattedResults) {
     tabs.set(
       passName,
       <TextTabContent
         output={text}
-        diff={passName !== "HIR" ? lastPassOutput : null}
-        showInfoPanel={true}
+        diff={lastPassOutput}
+        showInfoPanel={!nonDiffPasses.includes(passName)}
       ></TextTabContent>
     );
     lastPassOutput = text;
@@ -187,15 +188,15 @@ function Output({ store, compilerOutput }: Props) {
     });
   }, [store.source, compilerOutput]);
 
-  const changedPasses: Set<string> = new Set();
+  const changedPasses: Set<string> = new Set(["JS", "HIR"]); // Initial and final passes should always be bold
   let lastResult: string = "";
   for (const [passName, results] of compilerOutput.results) {
     for (const result of results) {
       let currResult = "";
       if (result.kind === "hir" || result.kind === "reactive") {
         currResult += `function ${result.fnName}\n\n${result.value}`;
       }
-      if (passName !== "HIR" && currResult !== lastResult) {
+      if (currResult !== lastResult) {
         changedPasses.add(passName);
       }
       lastResult = currResult;