fix: complete simple mode image workflows

[Minorli]

Summary

• expose received shares in simple mode and preserve ownership boundaries across reloads
• preserve source pixels outside edit masks and retain existing official logos without re-encoding or duplicate persistence
• show full result proportions, fix compact controls, and keep first-run guidance from covering actions
• release PicGen 0.1.62

Verification

• ./scripts/check.sh (406 passed, Ruff and Mypy clean)
• coverage: 87% total
• uv run --with pip-audit pip-audit (no known vulnerabilities)
• Playwright: 1440x900 and 375x812 simple inbox, share ownership, reload restore, download onboarding guard, full preview layout, existing-logo zero-upload path
• production 1:1 E2E matrix prepared for post-deployment validation

Production Test Plan

• simple: poster, image edit, itinerary, ranking, free create, same-style variant, share send/receive, refresh/restore
• professional: generate, variant, whole-image edit, masked edit, single reference, dual reference
• verify model routing, reasoning, true output dimensions, PNG mask pixel preservation, logo count/status, mobile layout, logs, DB records, and cleanup