Small UI gaps: SlotConnectionDot colors, FormDropdown type detection, OutputHistory pruning, Electron download type

## Recommendation

### 🔧 FINISH: Complete these minor UI feature gaps

Four small incomplete features:

## What Was Found

### SlotConnectionDot — No Connected/Disconnected Colors
- `src/renderer/extensions/vueNodes/components/SlotConnectionDot.vue:31` — `//TODO Support connected/disconnected colors?`

### FormDropdownMenuFilter — Missing Dialog Type Detection
- `src/renderer/extensions/vueNodes/widgets/components/form/dropdown/FormDropdownMenuFilter.vue:18` — `// TODO: Add real check to differentiate between the Model dialogs and Load Image` — Uses `filterOptions.length === 1` as a proxy heuristic.

### OutputHistory — Missing Output Pruning
- `src/renderer/extensions/linearMode/OutputHistory.vue:81` — `//TODO need to also prune outputs entries?` — Output entries may accumulate without being pruned, causing memory growth.

### Electron Download Store — Missing Type
- `src/stores/electronDownloadStore.ts:33` — `// ToDO: replace with ElectronDownload type` — Uses untyped `data` parameter.

## Context

These are individually small but collectively represent incomplete feature polish.

---

**Category:** Half-Implemented | **Confidence:** MEDIUM | **Tools:** Semantic analysis
_Filed by audit-code skill_

Part of #11022

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-11046-Small-UI-gaps-SlotConnectionDot-colors-FormDropdown-type-detection-OutputHistory-p-33e6d73d365081ceb505f9edb6c0d9e5) by [Unito](https://www.unito.io)