feat: add undo toast for skip, apply, and status moves

Accidental skips and status changes can be reversed within a few seconds via toast Undo, including bulk actions and keyboard shortcuts.

shared/src/types/jobs.ts

@@ -322,7 +322,8 @@ export interface UpdateJobInput {
   selectedProjectIds?: string;
   pdfPath?: string;
   tracerLinksEnabled?: boolean;
-  appliedAt?: string;
+  /** Pass `null` to clear (e.g. undo mark-as-applied). */
+  appliedAt?: string | null;
   coverLetter?: string | null;
   sponsorMatchScore?: number;
   sponsorMatchNames?: string;

shared/src/types/pipeline.ts

@@ -66,11 +66,22 @@ export type JobActionRequest =
       };
     };
 
+/** Snapshot used by client Undo toasts after skip / apply / move. */
+export type JobStatusRestore = {
+  jobId: string;
+  status: Job["status"];
+};
+
 export type JobActionResult =
   | {
       jobId: string;
       ok: true;
       job: Job;
+      /** Present when the action can be reversed (e.g. skip). */
+      undo?: {
+        previousStatus: Job["status"];
+        alsoSkipped?: JobStatusRestore[];
+      };
     }
   | {
       jobId: string;