Issue 002: Split app structure

[cody257]

Blocked by #1 — wait for PR #2 (test/lint foundation) to merge so this branch starts on a main that has CI gates in place.

Goal: make the app easy for multiple agents to edit.

Owned files

• src/App.jsx
• src/main.jsx
• new src/pages/*
• new src/layouts/*
• new src/features/*

Tasks

• Move landing screen out of App.jsx.
• Move buyer screen out of App.jsx.
• Move seller screen out of App.jsx.
• Add a small app shell.
• Keep behavior the same.

Acceptance criteria

• User can still pick buyer/seller.
• Seller generator still works.
• Buyer placeholder still renders.
• npm run lint, npm test, and npm run build all pass.
• GitHub Actions runs all three.

Branch / PR rules

• Branch name: agent/002-app-structure
• Branch from main after Issue 001: Test and lint foundation #1 has merged.
• Do not touch unrelated files (no package.json, no vite.config.js, no styling overhauls — those are later issues).
• Do not commit secrets.
• One PR, must pass CI, must be reviewed before merge.

Suggested split (non-binding)

• src/main.jsx keeps createRoot only.
• src/layouts/AppShell.jsx — header/footer chrome shared across pages.
• src/pages/LandingPage.jsx — buyer/seller picker.
• src/pages/SellerPage.jsx — current seller flow.
• src/pages/BuyerPage.jsx — current "Coming Soon" placeholder.
• src/App.jsx — route table only (state machine on userType is fine for MVP — no router library required).

Routing strategy is intentionally left to the implementer; the goal is clean file boundaries, not the choice between react-router and a state-machine.

Out of scope (deferred to later issues)

• Visual redesign / green palette → Issue 003.
• Replacing the seller form with chat → Issue 004.
• Building a real buyer flow → Issue 007.

See docs/HAGGLY_V2_AGENT_PLAN.md for the full plan and assignment prompt.