What Tax is — multi-year returns with K-1 fan-out

Tax handles small-business and personal entity returns: file a return, track its audit trail, compare across years, find missed deductions, and (for pass-throughs) fan K-1s out to partners and owners via the identity graph.

Tabs:
• **Overview** — current-year liability snapshot, status of each form.
• **Return** — the worksheet for the active year; line items grouped by form.
• **Forms** — the actual filed forms (1040, 1065, 1120S, schedules) per year.
• **Audit Trail** — immutable record of every change to a line item.
• **Filing** — filing status, payment vouchers, extension requests, e-file artifacts.

Entity types supported (driven by SUPPORTED_TAX_YEARS array):
- Sole Proprietor (Schedule C)
- Single-member LLC (Schedule C, default)
- Multi-member LLC / Partnership (Form 1065 + K-1s)
- S-Corp (Form 1120S + K-1s)
- C-Corp (Form 1120)

Pick the entity type and the relevant forms + line items auto-configure. Pass-through entities (Partnership, S-Corp) auto-generate K-1s for every owner/partner and distribute them via the platform identity graph — they appear in the recipient's /me/tax inbox without any email back-and-forth.