feat(core): Add step-based progress tracking, task metadata and enhanced TaskManager scheduling/metadata APIs

ts/taskbuffer.classes.taskstep.ts

@@ -0,0 +1,57 @@
+export interface ITaskStep {
+  name: string;
+  description: string;
+  percentage: number; // Weight of this step (0-100)
+  status: 'pending' | 'active' | 'completed';
+  startTime?: number;
+  endTime?: number;
+  duration?: number;
+}
+
+export class TaskStep implements ITaskStep {
+  public name: string;
+  public description: string;
+  public percentage: number;
+  public status: 'pending' | 'active' | 'completed' = 'pending';
+  public startTime?: number;
+  public endTime?: number;
+  public duration?: number;
+
+  constructor(config: { name: string; description: string; percentage: number }) {
+    this.name = config.name;
+    this.description = config.description;
+    this.percentage = config.percentage;
+  }
+
+  public start(): void {
+    this.status = 'active';
+    this.startTime = Date.now();
+  }
+
+  public complete(): void {
+    if (this.startTime) {
+      this.endTime = Date.now();
+      this.duration = this.endTime - this.startTime;
+    }
+    this.status = 'completed';
+  }
+
+  public reset(): void {
+    this.status = 'pending';
+    this.startTime = undefined;
+    this.endTime = undefined;
+    this.duration = undefined;
+  }
+
+  public toJSON(): ITaskStep {
+    return {
+      name: this.name,
+      description: this.description,
+      percentage: this.percentage,
+      status: this.status,
+      startTime: this.startTime,
+      endTime: this.endTime,
+      duration: this.duration,
+    };
+  }
+}