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-explorer.sh

@@ -1,66 +0,0 @@
-#!/bin/bash
-
-# Deploy AITBC Explorer to the server
-
-set -e
-
-SERVER="root@10.1.223.93"
-EXPLORER_DIR="/root/aitbc/apps/explorer-web"
-NGINX_CONFIG="/etc/nginx/sites-available/aitbc"
-
-echo "🚀 Deploying AITBC Explorer to Server"
-echo "====================================="
-echo "Server: $SERVER"
-echo ""
-
-# Colors
-GREEN='\033[0;32m'
-YELLOW='\033[1;33m'
-NC='\033[0m'
-
-print_status() {
-    echo -e "${GREEN}[INFO]${NC} $1"
-}
-
-print_warning() {
-    echo -e "${YELLOW}[WARN]${NC} $1"
-}
-
-# Build the explorer locally first
-print_status "Building explorer locally..."
-cd /home/oib/windsurf/aitbc/apps/explorer-web
-npm run build
-
-# Copy built files to server
-print_status "Copying explorer build to server..."
-scp -r dist $SERVER:$EXPLORER_DIR/
-
-# Update nginx config to include explorer
-print_status "Updating nginx configuration..."
-
-# Backup current config
-ssh $SERVER "cp $NGINX_CONFIG ${NGINX_CONFIG}.backup"
-
-# Add explorer location to nginx config
-ssh $SERVER "sed -i '/# Health endpoint/i\\
-    # Explorer\\
-    location /explorer/ {\\
-        alias /root/aitbc/apps/explorer-web/dist/;\\
-        try_files \$uri \$uri/ /explorer/index.html;\\
-    }\\
-\\
-    # Explorer mock data\\
-    location /explorer/mock/ {\\
-        alias /root/aitbc/apps/explorer-web/public/mock/;\\
-    }\\
-' $NGINX_CONFIG"
-
-# Test and reload nginx
-print_status "Testing and reloading nginx..."
-ssh $SERVER "nginx -t && systemctl reload nginx"
-
-print_status "✅ Explorer deployment complete!"
-echo ""
-echo "📋 Explorer URL:"
-echo "  🌐 Explorer: https://aitbc.bubuit.net/explorer/"
-echo ""