feat: remove code output footer, move actions to top bar, download .ll

- Remove global-toolbar (footer with code display) entirely
- Move Generate, Save, Load, New, Tests buttons to algorithm pane toolbar
- Replace prog.generateCode() with prog.generateAndDownload() — creates
  a Blob from the IR and triggers a program.ll download via a temp <a>
- Remove copyCode function from helpers.js (no longer needed)
- Remove global-toolbar and .code-output CSS rules
- Add .action-btn styling for the text buttons in pane-toolbar

wcprogram.js

@@ -208,12 +208,8 @@ class WCProgram extends HTMLElement {
     return lines.join("\n");
   }
 
-  generateCode() {
-    const outputEl = $id("ir-code");
-    if (!outputEl) { showError("Missing #ir-code output element"); return; }
-
+  _generateIR() {
     const { usedQuantities, usedUnits } = this._gatherUsedTypes();
-
     const typeDefs = this._generateTypeDefs(usedQuantities);
     const unitDefs = this._generateUnitDefs(usedUnits);
     const { boolDefs, scalarDefs, vectorDefs, stringDefs, arrayDefs } = this._generateVariableDeclarations();
@@ -225,24 +221,32 @@ class WCProgram extends HTMLElement {
       ? CodeGen.emitFlat(firstChild)
       : "; no flowchart body\n";
 
-    // Collect external function declarations from used libraries
     const proccalls = this.querySelectorAll("wc-proccall");
     const decls = this._generateLLVMDecls(proccalls);
 
-    // Collect string globals
     const strPool = CodeGen.getStringPool();
     const globals = strPool.map(function (_, i) { return CodeGen.stringGlobal(i); }).join("\n");
 
-    // Variable declarations -> alloca instructions in the prologue
     const dataSection = (boolDefs || scalarDefs || vectorDefs || stringDefs || arrayDefs)
       ? [boolDefs, scalarDefs, vectorDefs, stringDefs, arrayDefs]
           .filter(Boolean).map(function (s) { return s + "\n"; }).join("")
       : "";
 
-    const raw = CodeGen.generateIRFile(firstChild, decls, globals, dataSection);
-    outputEl.textContent = raw;
-    if (typeof hljs !== "undefined") hljs.highlightElement(outputEl);
-    outputEl.parentElement.dataset.language = "llvm";
+    return CodeGen.generateIRFile(firstChild, decls, globals, dataSection);
+  }
+
+  generateAndDownload() {
+    const ir = this._generateIR();
+    if (!ir) { showError("No IR to download"); return; }
+    const blob = new Blob([ir], { type: "text/plain" });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement("a");
+    a.href = url;
+    a.download = "program.ll";
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+    URL.revokeObjectURL(url);
   }
 }