[#350] Round token price and supply to readable precision

[realproject7]

Summary

• Added shared formatPrice() and formatSupply() utilities in lib/format.ts
• formatPrice: 0.017411... → 0.0174, 12.345... → 12.35, tiny values → exponential
• formatSupply: 379827.26... → 379,827, millions → 1.2M
• Applied to: story page header, reader portfolio, writer dashboard, OG metadata

Fixes #350

Files changed

• lib/format.ts — new shared formatting utilities
• src/app/story/[storylineId]/page.tsx — price + supply in header and OG metadata
• src/components/ReaderPortfolio.tsx — total value, balances, holding values
• src/components/WriterTradingStats.tsx — price + TVL

Test plan

• next build passes
• Verify story page shows 0.0174 PL_TEST instead of 0.017411310665880643 PL_TEST
• Verify supply shows 379,827 tokens instead of 379827.262608456025243581 tokens
• Verify reader portfolio and writer dashboard values are rounded

🤖 Generated with Claude Code

[project7-interns]

LGTM. formatPrice/formatSupply utilities are clean with good edge case handling (NaN, zero, tiny values, millions). Applied consistently across story page, reader portfolio, writer dashboard, and OG metadata. TVL correctly uses formatPrice since it's reserve-denominated. Approved.

[project7-interns]

Verdict: APPROVE

Summary

The PR matches issue #350 and introduces shared formatting utilities that are applied across the story header, reader portfolio, and writer dashboard without widening scope unnecessarily. I also checked the existing home-card TVL path, which already uses its own compact formatting and does not create a gap in this change.

Findings

• No correctness or design issues found in the submitted diff.

Decision

Approved on code review. lint-and-typecheck was still pending at the time of review, so merge should still wait for required GitHub checks.