MCP install targets

"permissions": ["mcp-registration"],
"contributes": {
  "mcpInstallTargets": [{
    "id": "com.example.agent/example-agent",
    "displayName": "Example Agent"
  }]
}

context.subscriptions.add(
  context.mcp.registerInstallTarget(
    'com.example.agent/example-agent',
    exampleMcpInstallTarget,
  ),
);

import { defineMcpInstallTarget } from '@terminay/extension-api';

const sameServer = (entry, server) =>
  JSON.stringify(entry) ===
  JSON.stringify({
    command: server.command,
    args: server.args,
    env: server.env ?? {},
  });

export const exampleMcpInstallTarget = defineMcpInstallTarget({
  async status({ server }) {
    try {
      const entry = (await readConfig()).mcpServers?.terminay;
      if (entry === undefined)
        return { state: 'not-installed', configPath: configPath() };
      return sameServer(entry, server)
        ? { state: 'installed', configPath: configPath() }
        : {
            state: 'changed',
            configPath: configPath(),
            message: 'The terminay entry points at a different command',
          };
    } catch {
      return {
        state: 'error',
        configPath: configPath(),
        message: 'The configuration file is not valid JSON',
      };
    }
  },
  async install({ server }) {
    const config = await readConfig();
    config.mcpServers = {
      ...config.mcpServers,
      terminay: {
        command: server.command,
        args: server.args,
        env: server.env ?? {},
      },
    };
    await writeConfig(config); // Write a temporary file, then rename it.
    return { ok: true, installed: true };
  },
  async uninstall() {
    const config = await readConfig();
    if (config.mcpServers?.terminay !== undefined) {
      delete config.mcpServers.terminay;
      await writeConfig(config);
    }
    return { ok: true, installed: false };
  },
});