[chore] Remove legacy history code (PR 3 of 3)

Removes legacy history API code and cleans up unused types from apiSchema.ts
now that the migration to Jobs API is complete.

Deleted files:
- src/platform/remote/comfyui/history/* (except reconciliation.ts)
- src/platform/workflow/cloud/getWorkflowFromHistory.ts
- src/platform/workflow/cloud/index.ts
- browser_tests/fixtures/utils/taskHistory.ts
- tests-ui/fixtures/history*.ts
- tests-ui/tests/platform/remote/comfyui/history/**
- tests-ui/tests/platform/workflow/cloud/getWorkflowFromHistory.test.ts

Cleaned up apiSchema.ts:
- Removed legacy tuple types (zQueueIndex, zExtraData, etc.)
- Removed RunningTaskItem, PendingTaskItem, HistoryTaskItem, TaskItem
- Kept only types still in use (WebSocket messages, TaskOutput, etc.)

Part of Jobs API migration. Depends on PR 2 (jobs-api-pr2-migration).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: ric-yu