Add OpenCode agent (10.8k stars, 319pt HN post)

OpenCode is a Go-based AI coding agent with a terminal TUI (Bubble Tea).
It natively supports OpenRouter as a built-in provider via OPENROUTER_API_KEY.

- Add opencode agent to manifest.json with env config
- Implement sprite/opencode.sh for Sprite cloud
- Implement hetzner/opencode.sh for Hetzner Cloud
- Add matrix entries (implemented: sprite, hetzner; missing: rest)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hetzner/opencode.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+set -eo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" 2>/dev/null && pwd)"
+# shellcheck source=hetzner/lib/common.sh
+if [[ -f "${SCRIPT_DIR}/lib/common.sh" ]]; then
+    source "${SCRIPT_DIR}/lib/common.sh"
+else
+    eval "$(curl -fsSL https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/hetzner/lib/common.sh)"
+fi
+
+log_info "OpenCode on Hetzner Cloud"
+echo ""
+
+ensure_hcloud_token
+ensure_ssh_key
+
+SERVER_NAME=$(get_server_name)
+create_server "${SERVER_NAME}"
+verify_server_connectivity "${HETZNER_SERVER_IP}"
+wait_for_cloud_init "${HETZNER_SERVER_IP}" 60
+
+log_warn "Installing OpenCode..."
+run_server "${HETZNER_SERVER_IP}" "curl -fsSL https://raw.githubusercontent.com/opencode-ai/opencode/refs/heads/main/install | bash"
+log_info "OpenCode installed"
+
+echo ""
+if [[ -n "${OPENROUTER_API_KEY:-}" ]]; then
+    log_info "Using OpenRouter API key from environment"
+else
+    OPENROUTER_API_KEY=$(get_openrouter_api_key_oauth 5180)
+fi
+
+log_warn "Setting up environment variables..."
+inject_env_vars_ssh "${HETZNER_SERVER_IP}" upload_file run_server \
+    "OPENROUTER_API_KEY=${OPENROUTER_API_KEY}"
+
+echo ""
+log_info "Hetzner server setup completed successfully!"
+log_info "Server: ${SERVER_NAME} (ID: ${HETZNER_SERVER_ID}, IP: ${HETZNER_SERVER_IP})"
+echo ""
+
+log_warn "Starting OpenCode..."
+sleep 1
+clear
+interactive_session "${HETZNER_SERVER_IP}" "source ~/.zshrc && opencode"