[Enhancement] Storyline page: redesign header with Moleskine cover + info layout

[realproject7]

Problem

The current storyline header (from PR #781) puts all info as separate stacked lines (title → Writer → plots/views → genre → rating). This is worse than before — it's a plain text dump with no visual structure.

New Design — Moleskine book cover + info panel (inspired by Korean web fiction stores like Ridi)

Wireframe

```
┌─────────────────────────────────────────────────────────┐
│ │
│ ┌──────────┐ Title (large, bold, accent) │
│ │ │ ★★★★★ 4.9 (76) · 👁 37 views │
│ │ GENRE │ │
│ │ │ Writer @project7 (with PFP) │
│ │ Title │ Plots 3 plots │
│ │ │ Genre Science Fiction │
│ │ │ │
│ │ N plots │ │
│ └──────────┘ │
│ │
└─────────────────────────────────────────────────────────┘
```

Layout Rules

• Desktop: Moleskine book cover on the LEFT (reuse existing Moleskine notebook styling from Reader tab holdings cards), info panel on the RIGHT
• Mobile: Book cover centered on top, info below (similar to holdings card mobile layout)
• The info panel should use a clean label-value list layout (like the Ridi reference), not inline text blobs
• Title is prominent at the top of the info panel
• Rating + view count on one line
• Writer with PFP on its own row
• Plot count and genre as label-value pairs

Reference

• Moleskine notebook styling: see Reader tab holdings cards in `src/app/profile/[address]/page.tsx` (~line 1490)
• Korean web fiction store (Ridi) layout: book cover left, structured info right with labeled rows

File

`src/app/story/[storylineId]/page.tsx` — `StoryHeader` component

Branch

`task/785-storyline-header-moleskine`