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).

client/src/lib/api.ts

@@ -3576,11 +3576,22 @@ export const api = {
       title?: string;
       tool?: LaneTool;
       credentials?: { username: string; password: string; remember?: boolean };
+      /** Blobless clone (`--filter=blob:none`): file contents fetched on checkout. */
+      partial?: boolean;
+      /** This clone's name for {@link lanes.cloneProgress}. */
+      progressToken?: string;
     }) =>
       request<{ lane: Lane; created: boolean; path: string }>("/lanes/clone", {
         method: "POST",
         body: JSON.stringify(body),
       }),
+    /**
+     * GET /api/lanes/clone/progress/:token — a clone's place in the
+     * machine-wide queue, then git's own progress; 404 until the POST
+     * carrying `progressToken` arrives, and a minute after it ends.
+     */
+    cloneProgress: (token: string) =>
+      request<CloneProgressView>(`/lanes/clone/progress/${encodeURIComponent(token)}`),
     /**
      * GET /api/lanes/pipelines — every pipeline template the server can render
      * a lane against, built-in plus any `DASHBOARD_PIPELINES_DIR` override.
@@ -3977,6 +3988,9 @@ export const api = {
         url: string;
         name?: string;
         credentials?: { username: string; password: string; remember?: boolean };
+        /** Blobless clone, like {@link lanes.clone}'s `partial`. */
+        partial?: boolean;
+        progressToken?: string;
       }
     ) =>
       request<LaneSourcesView & { path: string }>(`/lanes/${id}/sources/clone`, {
@@ -5290,6 +5304,23 @@ export interface LaneSource {
 }
 
 /** Response shape of GET /api/lanes/:id/sources (and of every sources write). */
+/** `GET /api/lanes/clone/progress/:token` — see server/lib/clone-queue.js. */
+export interface CloneProgressView {
+  state: "queued" | "running" | "done" | "failed";
+  /** 1-based place among the waiting clones while `queued`. */
+  position: number | null;
+  /** Clones running / waiting machine-wide, and how many may run at once. */
+  running: number;
+  waiting: number;
+  limit: number;
+  phase: "remote" | "receiving" | "resolving" | "checkout" | "other" | null;
+  /** git's own words for the phase (shown for `other`). */
+  label: string | null;
+  percent: number | null;
+  /** e.g. "450/1000, 120.50 MiB | 5.20 MiB/s". */
+  detail: string | null;
+}
+
 export interface LaneSourcesView {
   instructions: string;
   /** The workspace's tool can take folders and instructions (claude, codex). */