fix(share-pnl): group covers left, lift content block

[metodi96]

Summary

Tighten the share-PnL dialog layout: cluster the cover thumbnails on the left of the picker and shift the entire content block (PnL %, optional rows, timestamp) up so the bottom of the card no longer crowds the nolus.io brand line.

Changes

• Cover picker row: justify-between → flex-wrap justify-start gap-3. The three thumbnails now sit together at the left of the picker instead of being stretched across the dialog width.
• PNL_HERO_BASELINE_Y 430 → 380. Moves the big +XX.XX% hero up 50px.
• Optional-rows cursor 540 → 490. Entry price, mark price and position size move up with the hero so the spacing between the % block and the rows is preserved.
• Timestamp y 820 → 790. Adds 30px of breathing room between the date and the nolus.io brand line below it.

No behavioral change to canvas rendering, font specs, palette logic, or the PNG download / Web Share path.

Verification

• Ran npm run lint, npm test, and the worker bundle via the pre-commit hook — all clean.
• Opened the share dialog in the browser against a real lease, verified cover row groups left, hero + rows + timestamp move up together, and the timestamp is no longer flush against the nolus.io line.
• Checked all three cover variants (dark navy, orange, light lavender) and toggled the optional info checkboxes (PnL amount inline, prices, position size) — rows reflow with the new cursor without overlap.