test(e2e): cover the core editing, code intelligence, VCS, run and debug flows (#1277)

Adds a `stubDesktop` fixture that switches the browser-mode workbench to
desktop mode over a stubbed IPC layer: tests answer the commands they need,
push Channel messages and IdeEvents, and assert on the commands invoked.
Unstubbed commands fail as unavailable; documents keep the in-memory backend.

New flows covered:
- editing: modified marker and ⌘S save, ⌘R Replace All with one undo step
- code intelligence: completion, ⌘B to another file, Find Usages, in-place
  rename, diagnostics with an ⌥⏎ quick fix
- VCS: ⌘K commit with message validation and default inclusion
- run: ⌃R output streaming and exit, ⌘F2 stop
- debug: breakpoint, stop with frames and variables, step over, resume
- search: Find in Files results opening at the match line; the Search
  Everywhere file case no longer needs fixme
- terminal: typed command reaches the shell and its output renders
- project: Close Project to Welcome, trust prompt, open a recent project

e2e/commit.spec.ts

@@ -0,0 +1,75 @@
+/**
+ * Committing from the Commit tool window. Git is stubbed at the IPC layer; the repository side is
+ * covered by `crates/ide-vcs` against real repositories.
+ */
+import type { Page } from "@playwright/test";
+import { expect, ipcCalls, openFromTree, stubDesktop, test } from "./fixtures";
+
+const ROOT = "/dev/acme-api";
+
+/** A repository with a modified tracked file and an untracked one; `vcs_commit` clears both. */
+async function stubRepository(page: Page) {
+  await stubDesktop(page);
+  await page.evaluate(async (root) => {
+    let committed = false;
+    const changes = [
+      {
+        path: `${root}/build.gradle.kts`,
+        relPath: "build.gradle.kts",
+        staged: null,
+        unstaged: "modified",
+        renamedFrom: null,
+      },
+      { path: `${root}/notes.txt`, relPath: "notes.txt", staged: null, unstaged: "untracked", renamedFrom: null },
+    ];
+    const h = window.__ipc.handlers;
+    h.vcs_roots = () => [{ root, operation: null, head: "main", headCommit: "1111111" }];
+    h.vcs_branch_info = () => ({
+      head: "main",
+      headCommit: "1111111",
+      upstream: null,
+      ahead: 0,
+      behind: 0,
+      operation: null,
+    });
+    h.vcs_status = () => (committed ? [] : changes);
+    h.vcs_stage = () => null;
+    h.vcs_unstage = () => null;
+    h.vcs_commit = () => {
+      committed = true;
+      return "2222222";
+    };
+    const vcsModule = "/src/features/vcs/store.ts";
+    const { useVcs, refreshNow } = await import(/* @vite-ignore */ vcsModule);
+    useVcs.setState({ available: true, root, repo: root, branchesLoaded: false, stashesLoaded: false });
+    await refreshNow();
+  }, ROOT);
+}
+
+test("⌘K commits the checked changes with the typed message", async ({ workbench: page }) => {
+  await openFromTree(page, "build.gradle.kts");
+  await stubRepository(page);
+  await page.keyboard.press("Meta+k");
+  const panel = page.getByRole("region", { name: "Commit", exact: true });
+  const commit = panel.getByRole("button", { name: "Commit", exact: true });
+  const changes = panel.getByRole("tree", { name: "Changes" });
+  // Tracked changes start included; unversioned files start excluded.
+  await expect(changes.getByRole("checkbox", { name: "Include build.gradle.kts in commit" })).toBeChecked();
+  await expect(changes.getByRole("checkbox", { name: "Include Unversioned Files in commit" })).not.toBeChecked();
+  const message = panel.getByRole("textbox", { name: "Commit message" });
+  await expect(message).toBeFocused();
+
+  // Committing without a message is refused.
+  await commit.click();
+  await expect(panel.getByRole("alert")).toHaveText("Specify commit message");
+  expect(await ipcCalls(page, "vcs_commit")).toHaveLength(0);
+
+  await message.fill("Return order DTOs from create");
+  await commit.click();
+  await expect(page.getByText(/1 file committed: Return order DTOs from create/)).toBeVisible();
+  const [committed] = await ipcCalls(page, "vcs_commit");
+  expect(committed).toMatchObject({ repo: ROOT, message: "Return order DTOs from create" });
+  const staged = (await ipcCalls(page, "vcs_stage")).flatMap((a) => a.paths as string[]);
+  expect(staged).toEqual([`${ROOT}/build.gradle.kts`]);
+  await expect(changes.getByRole("checkbox", { name: "Include build.gradle.kts in commit" })).toBeHidden();
+});