feat(loops): edit instructions inline on loop detail

[MattPua]

Problem

Editing a loop's instructions on the detail page meant opening the full 4-step edit wizard just to tweak the prompt. The instructions were shown read-only in the config panel.

Changes

• Pull Instructions out of the shared Configuration panel into its own box
• The box is a textarea you click straight into to edit (no Edit/Save buttons)
• Saves on blur via the existing PATCH (useUpdateLoop); a subtle "Saving…" shows while in flight
• Escape reverts to the saved value without saving
• Guards: blank input reverts, no-op saves are skipped, textarea is disabled mid-save (no double-submit), errors revert and toast

How did you test this?

• pnpm --filter @posthog/ui typecheck passes
• biome check clean on the changed file
• Not manually run in-app yet

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code

[trunk-io]

😎 This pull request was merged.

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 1cafb41.}

[greptile-apps]

Prompt To Fix All With AI

Fix the following 2 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 2
packages/ui/src/features/loops/components/LoopDetailView.tsx:317-324
**Instruction Formatting Is Stripped**

When instructions contain meaningful leading spaces or trailing newlines, blur sends `value.trim()` instead of the text entered. The saved prompt silently loses that formatting; trimming should only detect blank input, while comparison and persistence should use the original value.

```suggestion
    if (!value.trim()) {
      if (textareaRef.current) textareaRef.current.value = loop.instructions;
      return;
    }
    if (value === loop.instructions || updateLoop.isPending) return;
    updateLoop.mutate(
      { instructions: value },
```

### Issue 2 of 2
packages/ui/src/features/loops/components/LoopDetailView.tsx:349-351
**Background Updates Discard Drafts**

The textarea key is the last saved instructions value, so a detail-query refresh that returns changed instructions remounts the field. If someone is typing when a window-focus refresh or concurrent update arrives, their unblurred draft disappears without warning.

_{Reviews (1): Last reviewed commit: "fix(loops): align inline editor with qui..." | Re-trigger Greptile}