API Keys & Tax Set-Aside

Added

• API key management — Full lifecycle with Argon2 hashing and Stripe-style UX
• API key authentication — External programmatic access via sk_live_* / sk_test_* Bearer tokens
• Tax set-aside widget — Dashboard shows estimated Corporation Tax liability with rate badges
• api.speybooks.com — New API subdomain with SSL via Let’s Encrypt

Changed

• Profit trend indicator hidden in first 7 days of month