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-blockchain-explorer.sh

@@ -1,94 +0,0 @@
-#!/bin/bash
-
-# Deploy blockchain explorer to incus container
-
-set -e
-
-echo "🔍 Deploying 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"
-}
-
-# Copy explorer to container
-print_status "Copying blockchain explorer to container..."
-ssh ns3-root "rm -rf /opt/blockchain-explorer 2>/dev/null || true"
-scp -r apps/blockchain-explorer ns3-root:/opt/
-
-# Setup explorer in container
-print_status "Setting up blockchain explorer..."
-ssh ns3-root << 'EOF'
-cd /opt/blockchain-explorer
-
-# Create Python environment
-python3 -m venv .venv
-source .venv/bin/activate
-pip install --upgrade pip
-pip install -r requirements.txt
-EOF
-
-# Create systemd service for explorer
-print_status "Creating systemd service for blockchain explorer..."
-ssh ns3-root << 'EOF'
-cat > /etc/systemd/system/blockchain-explorer.service << EOL
-[Unit]
-Description=AITBC Blockchain Explorer
-After=blockchain-rpc.service
-
-[Service]
-Type=exec
-User=root
-WorkingDirectory=/opt/blockchain-explorer
-Environment=PATH=/opt/blockchain-explorer/.venv/bin:/usr/local/bin:/usr/bin:/bin
-ExecStart=/opt/blockchain-explorer/.venv/bin/python3 main.py
-Restart=always
-RestartSec=5
-
-[Install]
-WantedBy=multi-user.target
-EOL
-
-systemctl daemon-reload
-systemctl enable blockchain-explorer
-EOF
-
-# Start explorer
-print_status "Starting blockchain explorer..."
-ssh ns3-root "systemctl start blockchain-explorer"
-
-# Wait for explorer to start
-print_status "Waiting for explorer to start..."
-sleep 3
-
-# Setup port forwarding for explorer
-print_status "Setting up port forwarding for explorer..."
-ssh ns3-root << 'EOF'
-# Add port forwarding for explorer
-iptables -t nat -A PREROUTING -p tcp --dport 3000 -j DNAT --to-destination 192.168.100.10:3000
-iptables -t nat -A POSTROUTING -p tcp -d 192.168.100.10 --dport 3000 -j MASQUERADE
-
-# Save rules
-iptables-save > /etc/iptables/rules.v4
-EOF
-
-# Check status
-print_status "Checking blockchain explorer status..."
-ssh ns3-root "systemctl status blockchain-explorer --no-pager | grep -E 'Active:|Main PID:'"
-
-print_success "✅ Blockchain explorer deployed!"
-echo ""
-echo "Explorer URL: http://192.168.100.10:3000"
-echo "External URL: http://aitbc.keisanki.net:3000"
-echo ""
-echo "The explorer will automatically connect to the local blockchain node."
-echo "You can view blocks, transactions, and chain statistics."