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-second-node.sh

@@ -1,127 +0,0 @@
-#!/bin/bash
-
-# Deploy a second blockchain node on the same server
-
-set -e
-
-echo "🚀 Deploying Second Blockchain Node"
-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"
-}
-
-# Create directory for second node
-print_status "Creating directory for second node..."
-NODE2_DIR="/opt/blockchain-node-2"
-sudo mkdir -p $NODE2_DIR
-sudo chown $USER:$USER $NODE2_DIR
-
-# Copy blockchain node code
-print_status "Copying blockchain node code..."
-cp -r /opt/blockchain-node/* $NODE2_DIR/
-
-# Create configuration for second node
-print_status "Creating configuration for second node..."
-cat > $NODE2_DIR/.env << EOF
-CHAIN_ID=ait-devnet
-DB_PATH=./data/chain2.db
-RPC_BIND_HOST=127.0.0.1
-RPC_BIND_PORT=8081
-P2P_BIND_HOST=0.0.0.0
-P2P_BIND_PORT=7071
-PROPOSER_KEY=node2_proposer_key_$(date +%s)
-MINT_PER_UNIT=1000
-COORDINATOR_RATIO=0.05
-GOSSIP_BACKEND=http
-GOSSIP_BROADCAST_URL=http://127.0.0.1:7070/gossip
-EOF
-
-# Create data directory
-mkdir -p $NODE2_DIR/data/devnet
-
-# Generate genesis file (same as first node)
-print_status "Generating genesis file..."
-cd $NODE2_DIR
-export PYTHONPATH="${NODE2_DIR}/src:${NODE2_DIR}/scripts:${PYTHONPATH:-}"
-python3 scripts/make_genesis.py --output data/devnet/genesis.json --force
-
-# Create systemd service
-print_status "Creating systemd service..."
-sudo cat > /etc/systemd/system/blockchain-node-2.service << EOF
-[Unit]
-Description=AITBC Blockchain Node 2
-After=network.target
-
-[Service]
-Type=exec
-User=root
-WorkingDirectory=$NODE2_DIR
-Environment=PATH=$NODE2_DIR/.venv/bin:/usr/local/bin:/usr/bin:/bin
-Environment=PYTHONPATH=$NODE2_DIR/src:$NODE2_DIR/scripts
-ExecStart=$NODE2_DIR/.venv/bin/python3 -m aitbc_chain.main
-Restart=always
-RestartSec=5
-
-[Install]
-WantedBy=multi-user.target
-EOF
-
-# Create RPC API service
-print_status "Creating RPC API service..."
-sudo cat > /etc/systemd/system/blockchain-rpc-2.service << EOF
-[Unit]
-Description=AITBC Blockchain RPC API 2
-After=blockchain-node-2.service
-
-[Service]
-Type=exec
-User=root
-WorkingDirectory=$NODE2_DIR
-Environment=PATH=$NODE2_DIR/.venv/bin:/usr/local/bin:/usr/bin:/bin
-Environment=PYTHONPATH=$NODE2_DIR/src:$NODE2_DIR/scripts
-ExecStart=$NODE2_DIR/.venv/bin/python3 -m uvicorn aitbc_chain.app:app --host 0.0.0.0 --port 8081
-Restart=always
-RestartSec=5
-
-[Install]
-WantedBy=multi-user.target
-EOF
-
-# Setup Python environment
-print_status "Setting up Python environment..."
-cd $NODE2_DIR
-python3 -m venv .venv
-source .venv/bin/activate
-pip install --upgrade pip
-pip install -e .
-
-# Enable and start services
-print_status "Enabling and starting services..."
-sudo systemctl daemon-reload
-sudo systemctl enable blockchain-node-2 blockchain-rpc-2
-sudo systemctl start blockchain-node-2 blockchain-rpc-2
-
-# Check status
-print_status "Checking service status..."
-sudo systemctl status blockchain-node-2 --no-pager -l
-sudo systemctl status blockchain-rpc-2 --no-pager -l
-
-echo ""
-print_status "✅ Second blockchain node deployed!"
-echo ""
-echo "Node 1 RPC: http://127.0.0.1:8080"
-echo "Node 2 RPC: http://127.0.0.1:8081"
-echo ""
-echo "To check logs:"
-echo "  Node 1: sudo journalctl -u blockchain-node -f"
-echo "  Node 2: sudo journalctl -u blockchain-node-2 -f"