feat: rebrand to Domain Scanner platform

Replace GeoExport static site with Next.js domain intelligence app:
real DNS/WHOIS/SSL/HTTP/geo scans, SSE progress, Docker stack,
updated install/uninstall scripts, and full documentation.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/ARCHITECTURE.md

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+# Architecture
+
+## Overview
+
+Domain Scanner is a Next.js 15 application with PostgreSQL (Prisma) and optional Redis caching. Scans run in-process on the web server using Node.js built-ins and public APIs.
+
+## Components
+
+```
+┌─────────────┐     ┌──────────────┐     ┌─────────────┐
+│   Browser   │────▶│  Next.js App │────▶│ PostgreSQL  │
+│  (SSE/REST) │     │  scan worker │     │   scans     │
+└─────────────┘     └──────┬───────┘     └─────────────┘
+                           │
+                    ┌──────▼───────┐
+                    │    Redis     │
+                    │ scan cache   │
+                    └──────────────┘
+```
+
+## Scan pipeline
+
+1. `POST /api/scan` validates domain, checks rate limit, creates `Scan` row
+2. Async `runDomainScan()` updates progress in DB
+3. Client subscribes to `GET /api/scan/:id/stream` (SSE)
+4. Completed results cached in Redis (1h) and stored as JSON in Postgres
+
+## Data model
+
+- **User** — credentials auth (NextAuth)
+- **Scan** — domain, status, progress, result JSON
+- **Monitor** — per-user DNS/SSL/uptime watch (cron stub)
+- **ApiRateLimit** — hourly per-IP counters
+
+## Competitive positioning
+
+Tools like DNSChecker and SecurityTrails focus on single-record lookups or enterprise datasets. Domain Scanner targets unified infrastructure snapshots with export and self-hosting — not a clone of their UI patterns.
+
+## Roadmap
+
+- BullMQ worker container for monitors
+- GraphQL server (schema placeholder in `src/lib/graphql/schema.ts`)
+- Blacklist checks (Spamhaus, etc.)
+- DNS diff history