fix: keep panel progress active when navigating away during categorization

[Harsh16gupta]

What was broken? (this was reported by a user on the forum -- I tried to reproduce the bug but was not able to do it.)
If you start the categorization pipeline and navigate away (like opening Tools → Options) while the model is loading or embeddings are being generated, the side panel resets to the initial "No categories yet" screen when you come back.

The pipeline was still running in the background, but the UI completely lost track of it. If a user clicked "Run" again at that point, it would also kick off a second redundant pipeline run.

What changes in this PR?

1. Prevent double runs: Added a check in setupPanel.ts so if operationState.inProgress is already true, clicking run just returns the current state instead of launching another pipeline.
2. Proper lifecycle tracking: Marked operationState.inProgress as true on start, and reset it to false inside onComplete and onError.
3. Fallback state on reconnect: Added a safety net in getInitialState so if the webview queries initial state while a background job is running, it receives a status update rather than an idle state.
4. Recovery polling on IPC delays: In AppStateContext.tsx, if the initial IPC response is delayed/missed because the main thread is busy loading models/embeddings, the webview will retry polling up to 5 times to catch back up with the running job.

[Harsh16gupta]

I wasn't able to test this as I couldn't reproduce the issue on my device. The changes only add extra guardrails but don't affect any working workflow, so I think we can merge it.