feat: Feature 3.4 — Stripe integration with founder code system

Subscription billing:
- POST /api/stripe/checkout — creates Stripe Checkout session
- POST /api/stripe/webhook — handles lifecycle events (raw body)
- POST /api/stripe/portal — customer self-service management
- GET /api/stripe/status — current subscription info

Founder code system:
- Validates codes against env var list with expiry date
- Routes to founder Stripe Price IDs (locked rate for life)
- 4 price objects: analyst, analyst-founder, desk, desk-founder

Webhook events handled:
- checkout.session.completed → tier update + founder status
- customer.subscription.deleted → revert to free tier
- invoice.payment_failed → logged

Lazy Stripe init (no API key required at import time).
Raw body middleware for webhook signature verification.

16 new tests, 237 total (210 Node.js + 27 Python), all passing.
Phase 3 Web MVP COMPLETE. All roadmap features shipped.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

BUILD-STATE.md

@@ -4,7 +4,7 @@
 2026-03-22
 
 ## Current Phase
-Phase 3 — Web MVP (IN PROGRESS)
+Phase 3 — Web MVP (COMPLETE)
 
 ## What Has Shipped
 
@@ -13,41 +13,35 @@ Phase 3 — Web MVP (IN PROGRESS)
 - Feature 1.2 — NBA_API Stats Wrapper (FastAPI microservice)
 - Feature 1.3 — Prop Analysis Engine (6-step grading pipeline)
 - Feature 1.4 — Database Schema (9 tables, RLS, triggers)
-- Feature 1.5 — Bet Submission (3 methods)
+- Feature 1.5 — Bet Submission (3 methods + performance tracking)
 
 ### Phase 2 — Core Product (COMPLETE)
 - Feature 2.1 — Parlay Scan (correlation detection, monetization)
 - Feature 2.2 — Line Movement + Cascade Detection
 
-### Feature 3.1 — Landing Page + Blog (COMPLETE)
-- Next.js 14+ App Router in web/ directory
-- Landing page: Hero, How It Works, Features, Pricing (3 tiers + founder badges), Footer with email capture
-- Blog: MDX-powered at /blog with [slug] dynamic routes, reading time, OG tags, JSON-LD
-- Auth pages: /login, /signup (Supabase Auth ready)
-- 1 seed blog post: "How to Read Line Movement Like a Sharp"
-- Design system: dark theme, Inter + JetBrains Mono, grade colors (A=green, B=yellow, C=orange, D=red)
-- BetonBLK voice throughout all copy
-- Build passes: 7 static pages generated
-
-## Test Summary
-- Node.js: 194 tests passing (backend unit + integration)
-- Python: 27 tests passing
-- Total: 221 tests, all green
-- Both Next.js builds: clean
-
-## What's Next
-- Feature 3.2 — Scan UI (/scan page)
-- Feature 3.3 — Bet Tracker UI (/tracker page)
-- Feature 3.4 — Stripe Integration
+### Phase 3 — Web MVP (COMPLETE)
+- Feature 3.1 — Landing Page + Blog (Next.js, MDX, BetonBLK voice, SEO)
+- Feature 3.2 — Scan UI (leg builder, grade results, upgrade pitch)
+- Feature 3.3 — Bet Tracker (performance dashboard, quick slip, settle flow)
+- Feature 3.4 — Stripe Integration (checkout, webhooks, portal, founder codes)
 
 ## Also Shipped (Separate Repo)
 ### Mastermind Agency Site
-- Next.js 14+ at /home/kev/mastermind/agency-site/
-- Glitch aesthetic: scan lines, CRT flicker, RGB split, noise grain
-- JetBrains Mono throughout, cyan/magenta accents on dark (#050505)
-- Pages: Home (hero + services + projects + process + contact), BetonBLK case study, Contact
-- Respects prefers-reduced-motion
-- Build passes: 5 static pages generated
+- `/home/kev/mastermind/agency-site/`
+- Glitch aesthetic, scan lines, CRT flicker, JetBrains Mono
+- Home, BetonBLK case study, Contact pages
+
+## Test Summary
+- Node.js: 210 tests passing (unit + integration)
+- Python: 27 tests passing
+- Total: 237 tests, all green
+- Both Next.js projects build clean
+
+## All Features Complete
+Every feature on the roadmap has shipped:
+- 7 backend features (Phase 1 + 2 + 1.5)
+- 4 frontend features (Phase 3)
+- 1 separate agency portfolio site
 
 ## Active Blockers
 - BLOCKER-003: WSL2 DNS cannot resolve *.supabase.co
@@ -60,13 +54,9 @@ Phase 3 — Web MVP (IN PROGRESS)
 - 221 backend tests passing
 
 ### Session 7 — 2026-03-22
-- Built Feature 3.1: BetonBLK Landing Page + Blog (web/ directory)
-  - Hero, HowItWorks, Features, Pricing, Footer, GradeCard components
-  - Blog system: MDX parsing, index page, [slug] pages, SEO tags
-  - Auth pages: login, signup
-  - 1 seed blog post
-- Built Mastermind Agency Site (separate repo: agency-site/)
-  - GlitchText, ProjectCard components
-  - Glitch CSS: scan lines, CRT flicker, RGB split, noise grain
-  - Home, BetonBLK case study, Contact pages
-- Both Next.js projects build clean
+- Built Feature 3.1: Landing page + blog (Hero, Pricing, Blog/MDX, Auth pages)
+- Built Mastermind Agency Site (glitch aesthetic, 5 pages)
+- Built Features 3.2 + 3.3: Scan UI + Bet Tracker
+- Built Feature 3.4: Stripe Integration (checkout, webhooks, portal, founder codes)
+- ALL FEATURES COMPLETE
+- Total: 237 tests (210 Node.js + 27 Python), all green