Rename product brand: Mandate → UnderWriter (backend + docs)

[trenchsheikh]

Why

The product is called UnderWriter, not "Mandate." The brand had been used inconsistently across the backend service and the docs (page titles, READMEs, env file headers, the contract file header, the PR-title prefix the amend agent emits, etc.). This PR renames the product brand to UnderWriter everywhere it appears, while keeping all domain language about the fund's investment mandate intact.

Frontend is intentionally not touched, per direction.

What's the brand vs what's domain language

Stays as "Mandate" / mandate (domain language)	Changed to "UnderWriter" (product brand)
MANDATE.md filename and # Mandate — Acme Ventures III heading inside it	Page/layout <title> tags
The Mandate desk (one of the six diligence desks; it parses MANDATE.md)	package.json description
lib/mandate-loader.ts, lib/mandate-evaluator.ts	backend/README.md, backend/.env.example headers
The Mandate TypeScript interface, loadMandate()	lib/contract.ts file header
The "mandate" desk id and source: "mandate" citation tag	agents/amend.ts PR-title prefix ([Mandate] → [UnderWriter])
Clause / section refs like "Mandate §2", "Mandate §4", "Mandate §5"	"Mandate platform" → "UnderWriter platform" in MANDATE.md prose
"the fund's mandate" prose	docs/Backend.md title and docs/DEMO.md brand mentions
	Root AGENTS.md overview

Rationale: a fund's investment mandate is a real, named document; the Mandate desk is the desk that parses it. Those names have meaning in the domain, independent of the product brand.

Files changed (13)

• backend/package.json, backend/README.md, backend/.env.example
• backend/app/layout.tsx, backend/app/page.tsx
• backend/lib/contract.ts
• backend/agents/amend.ts
• backend/scripts/smoke.ts
• backend/MANDATE.md, backend/docs/MANDATE.md (prose only)
• backend/docs/Backend.md, backend/docs/DEMO.md (titles and product-brand prose)
• AGENTS.md

Net: +25 / −23 lines.

Verification

Step	Result
npm run typecheck (tsc --noEmit)	clean
npm run build (next build)	clean, no warnings, all 4 routes registered
GET /api/health	{"status":"ok","service":"underwriter-backend",...}
Smoke: clean Acme deal	6/6 desks PASS → verdict proceed
Smoke: BEC Acme deal	5/6 PASS, wire-safety BLOCK → verdict hold; amendment diff captures acrne.co

The post-rename smoke transcript is attached:

backend_smoke_after_rename.txt

> running clean scenario
  [clean-acme] verdict proceed (PROCEED — 6/6 desks pass)

> running BEC scenario
  [bec-acme] verdict hold (HOLD — 1 blocking finding(s); 0 flag(s); 5 pass(es))
  blockingReason: Lookalike domain acrne.co vs verified acme.co (edit distance 2 ≤ 2) — wire_safety §6.2; Domain acrne.co age 6d < min 30d — wire_safety §6.1; DKIM fail on inbound wire-instruction email — wire_safety §6.3; ...

ALL CHECKS PASSED

Slack Thread