feat: enrich activity job display with manga/chapter context

- Add mangaTitle to ScrapingJob context at creation time
- Fix job.js constructor to map failureReason, attempts, maxAttempts, context from API
- JobItem: show readable type label, manga name, chapter number, source and attempts counter

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/vue/app/domain/activity/domain/entities/job.js

@@ -7,8 +7,12 @@ export class Job {
         payload = {},
         result = null,
         error = null,
+        failureReason = null,
         createdAt = new Date().toISOString(),
-        updatedAt = new Date().toISOString()
+        updatedAt = new Date().toISOString(),
+        attempts = 0,
+        maxAttempts = 1,
+        context = {}
     }) {
         this.id = id;
         this.type = type;
@@ -16,9 +20,12 @@ export class Job {
         this.progress = progress;
         this.payload = payload;
         this.result = result;
-        this.error = error;
+        this.error = failureReason ?? error;
         this.createdAt = createdAt;
         this.updatedAt = updatedAt;
+        this.attempts = attempts;
+        this.maxAttempts = maxAttempts;
+        this.context = context;
     }
 
     static create(data) {