chore: v2.8.12 — clone queue and progress, session defaults, chat agents, drops as @ mentions

Whole tree from parallel sessions, plus the version bump:
- Clone: a queue with live progress (Add workspace and extra folders),
  clones run under nice/ionice so the machine stays responsive.
- Settings → AI tools → Session defaults: a new session's default
  permission mode / bypass per account.
- Chat lists the background subagents that have not reported back yet.
- A file pasted or dropped into a claude pane goes in as an @ mention.
- Changes panel: say why amend/undo is refused on a pushed commit.
- openapi.yaml regenerated (Artifacts, Host, resumeById).

server/lib/git-identity.js

@@ -44,8 +44,8 @@ const gitCredentials = require("./git-credentials");
 const runAs = require("./run-as");
 
 const HOST_RE = /^[a-z0-9]([a-z0-9.-]*[a-z0-9])?(:\d{1,5})?$/;
-/** A clone may take a while on a big repo; past this it is killed. */
-const CLONE_TIMEOUT_MS = 10 * 60_000;
+/** A clone may take a while on a big repo (~1 GB); past this it is killed. */
+const CLONE_TIMEOUT_MS = 30 * 60_000;
 const HELPER = path.join(__dirname, "git-credential-helper.js");
 
 const err = (code, message) => Object.assign(new Error(message), { code });
@@ -841,15 +841,33 @@ function sshFailure(stderr) {
  * Clone `url` into `<parent>/<name>` as the account owning `parent`, with
  * that account's own identity. `once` is a login typed for this clone
  * (`{username, password, remember}`) — https only, for this URL's host only.
+ * `partial` makes it a blobless clone (`--filter=blob:none`): every commit
+ * and tree, but a file's contents only when a checkout first needs them —
+ * far less to download and unpack for a big repo, at the cost of a fetch
+ * from the remote when an old revision is checked out later.
  * Resolves `{dir, account}`; rejects with `ECREDENTIALS` (`{protocol, host}`
  * attached) when git wanted a login it did not get, `ESSHAUTH` when the key
  * was refused, else the git error.
  */
-async function cloneRepo({ url, parent, name, once = null }) {
+function cloneRepo({ job = null, ...opts }) {
+  // Waits for a free clone slot (clone-queue.js) before anything — a typed
+  // login sits in a member's store only while its own clone runs, and the
+  // timeout counts from there. `job` (clone-queue `track`) gets the queue
+  // position and git's progress.
+  const queue = require("./clone-queue");
+  return queue.withCloneSlot(
+    () => cloneNow(opts, queue.threads(), (chunk) => queue.report(job, chunk)),
+    job
+  );
+}
+
+async function cloneNow({ url, parent, name, once = null, partial = false }, threads, onProgress) {
   const { git } = require("./worktree");
   const account = accountForDir(parent);
   const remote = remoteOf(url);
-  const pre = [];
+  // index-pack's delta threads: this clone's share of the cores, not all of
+  // them (clone-queue.js). Not persisted — a later fetch keeps git's default.
+  const pre = ["-c", `pack.threads=${threads}`];
   const persist = [];
   const env = {};
   let restore = null;
@@ -911,9 +929,13 @@ async function cloneRepo({ url, parent, name, once = null }) {
 
   let ok = false;
   try {
-    await git(parent, [...pre, "clone", ...persist, "--", url, name], {
+    const filter = partial ? ["--filter=blob:none"] : [];
+    // --progress: git prints it to a pipe too, for the UI's progress line.
+    await git(parent, [...pre, "clone", ...persist, "--progress", ...filter, "--", url, name], {
       timeout: CLONE_TIMEOUT_MS,
       env,
+      background: true,
+      onStderr: onProgress,
     });
     ok = true;
   } catch (e) {
@@ -932,9 +954,7 @@ async function cloneRepo({ url, parent, name, once = null }) {
     }
     throw err(
       "ECLONE",
-      String(stderr || e.message)
-        .trim()
-        .slice(-800)
+      (require("./clone-queue").stripProgress(stderr) || e.message).trim().slice(-800)
     );
   } finally {
     // A login typed without "remember" — or one that did not work — leaves