Webhooks, Request Log & Tax Set-Aside

Added

• Webhook management — Full CRUD for webhook endpoints with signing secrets and event filtering
• API request log — Track all API key authenticated requests with method, status, and timing
• Tax set-aside: VAT support — Dashboard widget handles three VAT schemes (not registered, standard, flat rate)
• Quick start section — Developer tab shows org ID, API base URL, and curl example
• 13 webhook event types — Invoices, quotes, contacts, transactions, and payments

Changed

• CT threshold corrected from £50k to £250k (UK small profits rate)
• API key creation migrated from raw fetch to shared axios client
• Filter dropdowns replaced with Radix UI Select component
• Public webhook path narrowed to /api/v1/webhooks/stripe only