Unsaved changes indicator, premium-gated fields, spending power fix, and unsubscribe links

A round of fixes and polish since the last update.

Unsaved changes indicator

The Save button now highlights when your scenario has changes that have not been saved. No more wondering whether you remembered to save before closing the tab.

Premium-gated fields with lock icon

Fields that require Premium - like per-holding return rates and custom fee rates - now show a lock icon instead of silently ignoring your input. Clicking the lock opens the upgrade modal directly, so you know exactly what you are unlocking.

Spending power calculation fix

The spending power figure was showing different results between the simple and full FIRE calculators. This has been corrected - both now use the same calculation, so the number you see on the simple calc matches what the full calc produces.

Scenario load flash fix

When loading a saved scenario, the calculator briefly flashed the default projection before showing your actual numbers. This was caused by a timing issue between the scenario loading and the calculation running. Fixed - your saved numbers now appear immediately.

Under the hood

• Yahoo Finance price fetcher now retries with backoff on transient failures
• Auth0 error pages now show a friendly message instead of a raw error
• Friendly error handling when Auth0 redirects back with an error