Grant Chat AI completion and Exchange chat export (#705)

ddiff --git a/server/identity/principals.js b/server/identity/principals.js
iindex e421f8cb..97491397 100644
---- a/server/identity/principals.js
++++ b/server/identity/principals.js
@@@ -163,8 +163,10 @@ const DEFAULT_GRANTS = [
      // the chat-AI summaries run in Chat with its own token.
      ['chat', 'media.object.upload', 'openvibe.media', ['chat']],
      ['chat', 'media.object.delete', 'openvibe.media', ['chat']],
--    ['chat', 'ai.run.create', 'openvibe.ai', ['chat.*']],
++    ['chat', 'ai.run.create', 'openvibe.ai', ['chat.*', 'ai.complete']],
      ['chat', 'ai.run.read', 'openvibe.ai', ['chat.*']],
++    // Activated when Contracts includes exchange.chat.export; only Chat imports a person's old chats.
++    ...(capabilities.get('exchange.chat.export') ? [['chat', 'exchange.chat.export', 'openvibe.exchange', []]] : []),
      // Chat's AI members linked to a Food household read its pantry and plan (food.household.read; Contracts 0.189.0).
      ['chat', 'food.household.read', 'openvibe.food', []],
      // Vibe on openvibe.chat (Chat#139) searches the open web through Actor for the person it is talking with: Chat
@@@ -964,6 +966,7 @@ const RESTORED_GRANTS = [
  ];
  
  const CHANGED_DEFAULT_NAMESPACES = [
++    ['chat', 'ai.run.create', 'openvibe.ai', ['chat.*'], ['chat.*', 'ai.complete']],
      ['live', 'network.modules.write', SELF_AUDIENCE, ['chat.preferences', 'chat.tts_defaults', 'live.profile'], ['chat.tts_defaults', 'live.profile']],
      ['live', 'network.modules.write', SELF_AUDIENCE, ['chat.tts_defaults', 'live.profile'], ['live.profile', 'live.stats']],
      ['live', 'network.modules.read', SELF_AUDIENCE, ['chat.preferences', 'chat.tts_defaults', 'live.profile'], ['live.profile', 'live.stats']],