Redesign Portfolio tab v2 — complete mobile-friendly redesign

[realproject7]

Problem (Image 223)

The Portfolio tab redesign from PR #707 is messier on mobile than before. Toggle buttons make it worse. Need a complete mobile-friendly redesign.

Requirements

• Remove ALL toggle/collapse buttons — everything visible
• Mobile-first layout — design for 375px first, then scale up
• Clean visual hierarchy — portfolio value prominent, then holdings, then donations, then trades
• Use `/frontend-design` skill for a fresh approach

Information to display (all visible, no hiding)

1. Portfolio summary: total value (PLOT + USD), token count, best 24h pick
2. Token holdings: per-token cards with name, genre, value, balance, price, entry price, 24h change, last traded
3. Donations: received total + given total with per-story breakdown
4. Trading history: buy/sell rows with story name, tokens, cost, date

Design constraints

• No toggle/collapse/accordion patterns
• Must not overflow on mobile
• Consistent card styling
• PlotLink terminal aesthetic

Files to modify

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

Branch

`task/710-portfolio-mobile-redesign`

Self-Verification (T3)

• Zero toggle/collapse buttons on the page
• Mobile (375px): clean, readable, no overflow
• All info visible: portfolio, holdings, donations, trades
• Desktop: good use of horizontal space
• `npm run build` passes