feat: split job history into a dedicated sidebar tab (#8957)

## Summary

Move queue job history into a dedicated sidebar tab (gated by `Comfy.Queue.QPOV2`) and remove mixed job-history UI from the Assets sidebar so assets and job controls are separated.

## Changes

- **What**:
  - Added `JobHistorySidebarTab` with reusable job UI primitives: `JobFilterTabs`, `JobFilterActions`, `JobAssetsList`, and shared `JobHistoryActionsMenu`.
  - Added reactive `job-history` tab registration in `sidebarTabStore`; prepends above Assets when `Comfy.Queue.QPOV2` is enabled and unregisters cleanly when disabled.
  - Added debounced search to `useJobList` (filters by job title, metadata, and prompt id).
  - Extracted clear-history dialog logic to `useQueueClearHistoryDialog` and reused it from queue overlay and job history tab.
  - Removed active-job rendering and queue-clear controls from assets list/grid/tab views; assets sidebar now focuses on media assets only.
  - Removed the QPOV2 gate from `MediaAssetViewModeToggle` and updated queue/job localized copy.
  - Added and updated tests for queue overlay header actions, job filters, search filtering, sidebar tab registration, and assets sidebar behavior.

## Review Focus

- Verify QPOV2 toggle behavior:
  - `Docked Job History` menu action toggles `Comfy.Queue.QPOV2`.
  - `job-history` tab insertion/removal order and active-tab reset on removal.
- Verify behavior split between tabs:
  - Job controls (cancel/delete/view/filter/search/clear history/clear queue) live in Job History.
  - Assets sidebar loading/empty states and list/grid rendering remain correct after removing active jobs.

## Screenshots (if applicable)
<img width="670" height="707" alt="image" src="https://github.com/user-attachments/assets/3a201fcb-d104-4e95-b5fe-49c4006a30a5" />

src/locales/en/main.json

@@ -825,11 +825,14 @@
       "showAssetsPanel": "Show assets panel",
       "queuedSuffix": "queued",
       "clearQueued": "Clear queued",
-      "clearHistory": "Clear job queue history",
+      "clearHistory": "Clear job history",
+      "dockedJobHistory": "Docked Job History",
+      "clearHistoryMenuAssetsNote": "Media assets won't be deleted.",
       "filterJobs": "Filter jobs",
       "filterBy": "Filter by",
       "filterAllWorkflows": "All workflows",
       "filterCurrentWorkflow": "Current workflow",
+      "searchJobs": "Search...",
       "sortJobs": "Sort jobs",
       "sortBy": "Sort by",
       "activeJobs": "{count} active job | {count} active jobs",