Remote runners - handle deleted jobs and move on

[ilfarpro]

Description

When a remote runner was processing a transcoding job that got deleted from the PeerTube server, it would:

1. Continue processing the job

2. Generate repeated 404 errors on progress updates

3. Waste resources completing the transcoding

4. Eventually fail when trying to send success

5. Generate more errors trying to report the failure

6. Enhanced scheduleTranscodingProgress (common.ts)

• Now detects 404 errors from job update calls
• When a job is deleted (404 response), it:
• Logs an informative message
• Stops sending further updates
• Calls an optional onAbort callback
• Clears the update interval

2. Updated All Job Processors

• Modified all VOD transcoding functions to handle abortion gracefully:
• Web Video Transcoding (processWebVideoTranscoding)
• HLS Transcoding (processHLSTranscoding)
• Audio Merge Transcoding (processAudioMergeTranscoding)
• Studio Transcoding (processStudioTranscoding)
• Video Transcription (processVideoTranscription)
• Storyboard Generation (processGenerateStoryboard)
  Each now:
• Uses an onAbort callback to set a jobAborted flag
• Checks jobAborted after async operations (downloads, transcoding)
• Returns early without sending success if aborted
• Catches errors and silently returns if the job was aborted

Has this been tested?

• 👍 yes, I added tests to the test suite
• 💭 no, because this PR is a draft and still needs work
• 🙅 no, because this PR does not update server code
• 🙋 no

Sorry, haven't tested yet.

[Chocobozzz]

Can you add tests? :)