docs: restructure website, optimize HTML, gitignore private files

Website docs (website/docs/):
- Delete 6 stale -md.html duplicates
- Rename docs-clients/miners/developers → clients/miners/developers.html
- Unify header/nav across all 15 pages (new .site-header pattern)
- Fix 34 dead href=# links with real targets
- Upgrade Font Awesome v4→v6 in index.html
- Replace search stub with live client-side search (15-page index)
- Extract all inline CSS into shared docs.css (+630 lines)
- Extract inline theme JS into shared theme.js
- Strip inline style= attributes from 10+ pages
- Add .announce-banner, .source-links, .search-results CSS classes
- Add Markdown Source links to clients/miners/developers pages
- Update components.html title to Architecture & Components
- Move browser-wallet.html to website/wallet/, leave redirect
- Update all dates to February 2026

Website root:
- Delete 6 root-level duplicate HTML files (160KB saved)
- Rewire index.html and 404.html links

Root README.md:
- Fix 8 broken doc links to new numbered folder structure
- Update copyright to 2026

.gitignore + .example files:
- Gitignore private files: .aitbc.yaml, .env, deploy scripts,
  GPU scripts, service scripts, infra configs, .windsurf/, website README
- Create 7 .example files for GitHub users with sanitized templates
- Untrack 47 previously committed private files

Live server:
- Push all website files to aitbc-cascade:/var/www/html/
- Clean stale admin.html and index.nginx-debian.html

scripts/deploy/deploy-modern-explorer.sh

@@ -1,56 +0,0 @@
-#!/bin/bash
-
-# Deploy Modern Blockchain Explorer
-
-set -e
-
-echo "🚀 Deploying Modern Blockchain Explorer"
-echo "======================================"
-
-# Colors
-GREEN='\033[0;32m'
-YELLOW='\033[1;33m'
-NC='\033[0m'
-
-print_status() {
-    echo -e "${GREEN}[INFO]${NC} $1"
-}
-
-print_warning() {
-    echo -e "${YELLOW}[WARN]${NC} $1"
-}
-
-# Stop existing services
-print_status "Stopping existing services..."
-systemctl stop nginx 2>/dev/null || true
-
-# Create directory
-print_status "Creating explorer directory..."
-rm -rf /opt/blockchain-explorer
-mkdir -p /opt/blockchain-explorer/assets
-
-# Copy files
-print_status "Copying explorer files..."
-cp -r /opt/blockchain-node-src/apps/blockchain-explorer/* /opt/blockchain-explorer/
-
-# Update nginx configuration
-print_status "Updating nginx configuration..."
-cp /opt/blockchain-explorer/nginx.conf /etc/nginx/sites-available/blockchain-explorer
-ln -sf /etc/nginx/sites-available/blockchain-explorer /etc/nginx/sites-enabled/
-rm -f /etc/nginx/sites-enabled/default
-
-# Test and start nginx
-print_status "Starting nginx..."
-nginx -t
-systemctl start nginx
-
-print_success "✅ Modern explorer deployed!"
-echo ""
-echo "Access URLs:"
-echo "  - Explorer: http://localhost:3000/"
-echo "  - API: http://localhost:3000/api/v1/"
-echo ""
-echo "Standardized API Endpoints:"
-echo "  - GET /api/v1/chain/head"
-echo "  - GET /api/v1/chain/blocks?limit=N"
-echo "  - GET /api/v1/chain/blocks/{height}"