Pause and save queue

[KyleTryon]

Issue: Support pausing and resuming render queues

Problem

Rendering large batches of projects can span multiple days. If a user needs to stop the application mid-queue, the current workflow forces them to:

1. Wait for the current task to finish
2. Quit the application
3. Manually remove already-complete tasks from the queue
4. Restart and reconfigure the queue later

Proposed Solution

1. Persist queue state
   • After each task completes, serialize the remaining queue and current progress into the user’s config file.
2. Pause/stop functionality
   • Add a CLI command or keybinding (pause / stop) that immediately writes out the queue state, including the last completed frame for any in-progress task.
3. Auto-resume on launch
   • On application startup, detect a saved queue state. Prompt the user to either:
     • Resume the saved queue (pick up where they left off)
     • Discard and start a fresh queue