Reader tab v6 — Moleskine holdings layout matching Writer tab

[realproject7]

Overview

Rename "Portfolio" tab to "Reader". Redesign token holdings to use the same Moleskine left + info right layout as the Writer tab, since portfolio items are also story books.

Layout specification

Portfolio summary (unchanged from v4/v5)

```
PORTFOLIO ← section title outside box

┌──────────────────────────────────┐
│ Value: 37.56 PLOT ($0.661) │
│ Tokens: 1 │
│ Best 24h: Straton +5.5% │
└──────────────────────────────────┘
```

TOKEN HOLDINGS section

```
TOKEN HOLDINGS ← section title

┌──────────────────────────────────┐
│ ┌─────────┐ │
│ │ SCIENCE │ 37.56 PLOT ($0.661) │
│ │ FICTION │ +5.5% │
│ │ │ Balance: 12,000 │
│ │ Straton │ Price: 0.0031 PLOT │
│ │ │ Entry: 0.0031 PLOT │
│ │ │ Traded: Mar 31 │
│ └─────────┘ │
└──────────────────────────────────┘
```

• Moleskine book on left (genre, title — same as home page and Writer tab)
• Value + change + stats on right
• Side-by-side on sm+, stacked on mobile

DONATIONS section

Keep current structured layout — Received/Given with rows.

TRADES section

Keep current structured layout — Buy/Sell rows.

Use `/frontend-design` skill

Files to modify

• `src/app/profile/[address]/page.tsx` — rename tab, redesign Portfolio/Reader section

Branch

`task/731-reader-tab-v6`

Self-Verification (T3)

• Tab renamed from "Portfolio" to "Reader"
• Token holdings use Moleskine left + info right layout
• Moleskine book matches home page / Writer tab design
• Mobile (375px): stacks gracefully
• Donations + Trades sections clean
• `npm run build` passes