# Task: Redesign content editor for shared multi-channel previews

## Feature

`docs/FEATURES/channels.md`

## Goal

Make content creation feel like planning a real social post instead of filling out legacy form fields.

The editor should use one shared content body for every selected target channel, show selectable target channels as a vertical tab-style list, and preview the same content in platform-shaped cards for networks such as YouTube and X.

## Scope

- Keep content item editing in `frontend/src/features/content/views/ContentItemDetailView.vue`.
- Replace per-channel caption editing with a shared caption and shared hashtags.
- Let configured workspace channels be selected or unselected as targets.
- Show selected targets in a vertical rail and render preview cards that look closer to social platform previews.
- Convert shared hashtags into chip-style entry with suggestions from already used hashtags.
- Show a workspace hashtag feed so authors can reuse existing tags.
- Preserve existing save payloads and backend contracts.

## Validation

```bash
cd frontend
npm run build
```

## Acceptance Criteria

- [x] Content authors select target channels with checkbox-like controls.
- [x] The same shared content appears on every selected channel preview.
- [x] The editor includes platform-specific preview treatment for YouTube and X/Twitter.
- [x] Saving still creates or revises a content item with the selected targets.
- [x] Hashtags commit to removable chips as they are entered.
- [x] Already used hashtags are available as suggestions.
- [x] The editor shows a workspace hashtag feed with usage counts.