fix(llm-analytics): show error state on sentiment API failure

[okxint]

Problem

When the sentiment generations endpoint (/api/environments/{id}/llm_analytics/sentiment/generations/) returns a 500 error, the kea loader dispatches loadGenerationsFailure but the generations state stays as []. The UI treats generations.length === 0 as "no data" and renders the empty-state copy ("No generations with user input found"), which misleads users into thinking there is simply nothing to show rather than signalling that something went wrong.

Closes #58341

Changes

llmAnalyticsSentimentLogic.ts — add generationsError reducer:

• Set to true on loadGenerationsFailure
• Reset to false on loadGenerations (new fetch started) and loadGenerationsSuccess

LLMAnalyticsSentiment.tsx — check generationsError before the empty-state branch:

• Show "Failed to load generations — try refreshing the page" when the API call errored
• Leave the existing empty-state and loading paths unchanged

How did you test this code?

Traced the kea loader lifecycle: loaders dispatch *Failure actions on thrown errors; kea does not expose a built-in error state on the generated selectors, so the new reducer is the standard kea pattern for this. Ran the frontend formatter (passed).

Publish to changelog?

No

Docs update

No docs change needed.

🤖 Agent context

Identified the gap by reading the loader definition and the UI branch: generations === [] covered both the "no data" and "load failed" cases with identical copy. Added a minimal reducer to distinguish the two states without touching the loader logic or the fetch function.

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix(llm-analytics): show error state on ..." | Re-trigger Greptile}

[github-actions]

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[deployment-status-posthog]

Deploy status

Environment	Status	Deployed At	Workflow
dev	✅ Deployed	2026-05-21 15:53 UTC	Run
prod-us	✅ Deployed	2026-05-21 16:10 UTC	Run
prod-eu	✅ Deployed	2026-05-21 16:10 UTC	Run