feat(files): New → Clone repository clones into the open folder

The File Explorer's New menu (and its right-click menu) gains Clone
repository: it clones a URL into the folder it has open — of the user's own
home or of a workspace's own folder — through POST /api/lanes/clone with
that folder as `parent`, so the URL allowlist, the own-folder check and the
folder account's own git identity all apply, and opens a workspace on the
clone. ECREDENTIALS asks for a login, ESSHAUTH points to Settings → Git.
GET /api/homes now gives `me` its absolute `dir`. Keys typed in the dialog
never reach the explorer's shortcuts (Backspace / Delete).

server/__tests__/home-files.test.js

@@ -79,6 +79,8 @@ describe("File Explorer on the home", () => {
       r.body.homes.map((h) => [h.id, h.readOnly]),
       [["me", false]]
     );
+    // Its absolute folder: where the Files page's Clone repository clones to.
+    assert.equal(r.body.homes[0].dir, path.resolve(HOME));
   });
 
   it("lists the home with every top-level dot entry hidden", async () => {

server/lib/homes.js

@@ -49,14 +49,23 @@ function homeOf(user) {
 }
 
 /**
- * The homes `req` may open: `{ id: "me" | <username>, label, readOnly }`.
+ * The homes `req` may open: `{ id: "me" | <username>, label, readOnly }`,
+ * `me` with its absolute `dir`.
  * Others' only for an admin, and only those that resolve to a folder.
  */
 function listHomes(req) {
   const out = [];
   const me = req.user || null;
-  if (homeOf(me))
-    out.push({ id: "me", label: me?.displayName || me?.username || "", readOnly: false });
+  const mine = homeOf(me);
+  // `dir` for the caller's own home only: the Files page clones into it.
+  if (mine) {
+    out.push({
+      id: "me",
+      label: me?.displayName || me?.username || "",
+      readOnly: false,
+      dir: path.resolve(mine),
+    });
+  }
   if (me?.role === "admin" && auth.isServerMode()) {
     for (const u of auth.listUsers()) {
       if (u.id === me.id || u.disabled) continue;