feat(debugger): Browse the debug console history and open diff settings from the keyboard (#162)

- Debug console: typed expressions are kept per project, and Browse Console
  History (⌥⌘E / Ctrl+Alt+E) lists them, most recent first, to put one back
  into the input.
- Diff viewer: Diff Settings (⇧⌘D / Ctrl+Shift+D) opens the viewer options
  (side-by-side / unified, whitespace, highlighting, collapsing, scroll sync)
  as a popup menu.

src/features/debugger/ui/DebugToolWindow.tsx

@@ -39,6 +39,7 @@ import {
   type DebugSession,
 } from "../state";
 import { VariablesView, type VarRoot } from "./VariablesView";
+import { pushHistory, readHistory, setConsoleHistoryBrowser } from "./expressionHistory";
 import styles from "./DebugToolWindow.module.css";
 import { tx } from "@/platform/i18n";
 
@@ -542,8 +543,9 @@ function ConsoleView({ session }: { session: DebugSession }) {
   const scroller = useRef<HTMLDivElement>(null);
   const stick = useRef(true);
   const [input, setInput] = useState("");
-  const history = useRef<string[]>([]);
+  const history = useRef<string[]>(readHistory("console"));
   const historyPos = useRef(-1);
+  const inputRef = useRef<HTMLInputElement>(null);
 
   useEffect(() => {
     const el = scroller.current;
@@ -553,7 +555,8 @@ function ConsoleView({ session }: { session: DebugSession }) {
   const submit = async () => {
     const e = input.trim();
     if (!e) return;
-    history.current = [e, ...history.current.filter((h) => h !== e)].slice(0, 100);
+    pushHistory("console", e);
+    history.current = readHistory("console");
     historyPos.current = -1;
     setInput("");
     appendConsole(session.id, "input", `> ${e}\n`);
@@ -565,6 +568,24 @@ function ConsoleView({ session }: { session: DebugSession }) {
     }
   };
 
+  /** IDEA's Browse History popup: the expressions typed before, most recent first. */
+  const browseHistory = () => {
+    const el = inputRef.current;
+    const r = el?.getBoundingClientRect();
+    const items: MenuItem[] = history.current.length
+      ? history.current.slice(0, 30).map((h, i) => ({
+          id: String(i),
+          label: h.length > 120 ? `${h.slice(0, 120)}…` : h,
+          run: () => {
+            setInput(h);
+            historyPos.current = i;
+            el?.focus();
+          },
+        }))
+      : [{ id: "none", label: "No history", disabled: true }];
+    showContextMenu({ x: r?.left ?? 120, y: (r?.top ?? 200) - 4 }, items);
+  };
+
   const onKeyDown = (e: KeyboardEvent<HTMLInputElement>) => {
     if (e.key === "Enter") {
       e.preventDefault();
@@ -607,7 +628,10 @@ function ConsoleView({ session }: { session: DebugSession }) {
           ›
         </span>
         <input
+          ref={inputRef}
           className={styles.evalInput}
+          onFocus={() => setConsoleHistoryBrowser(browseHistory)}
+          onBlur={() => setConsoleHistoryBrowser(null)}
           value={input}
           onChange={(e) => setInput(e.target.value)}
           onKeyDown={onKeyDown}