Add Catch-Up Centre product + expand Accounting feature set #3908

Originally written by @ccantynz-alt on GitHub.
Imported from https://github.com/ccantynz-alt/MarcoReid.com/pull/35

Position Marco Reid Accounting as the most advanced accounting platform by making the feature set explicit about what we actually cover:

• Payroll across NZ PAYE, AU PAYG, US federal + 50 state withholding, UK PAYE, and CA CPP/EI
• GST / VAT / sales tax filing across NZ, AU, UK, and all 50 US states
• Provisional, estimated, and year-end income tax
• Autonomous (not just automated) bookkeeping
• Direct e-filing to IR, IRS, ATO, HMRC, and CRA
• Akahu bank feeds for NZ in addition to Plaid

Add a new Catch-Up Centre product entry for clients who are years behind on taxes. AI reconstructs missing books from statements and receipts, back-files GST and income tax, recalculates provisional tax, drafts penalty-remission letters, and lodges everything with a qualified accountant signing off before filing.

Wire /catch-up-centre into the top navigation so it's discoverable from every marketing page.