Network: media-hub may write its own Search documents (search.document.write), for OpenVibe.Video's public uploads (#234)

ddiff --git a/server/identity/principals.js b/server/identity/principals.js
iindex 6533319e..65b4e48c 100644
---- a/server/identity/principals.js
++++ b/server/identity/principals.js
@@@ -441,6 +441,8 @@ const DEFAULT_GRANTS = [
      ...['live', 'chat', 'community'].flatMap(c => ['tools.tool.run', 'tools.job.read'].map(cap => [c, cap, 'openvibe.tools', []])),
      // Tools indexes its own tool pages in Search through the owner API (owner tools only).
      ['tools', 'search.document.write', 'openvibe.search', []],
++    // OpenVibe.Video's public uploads in Search through the owner API (owner media-hub; Events cannot carry a hyphen).
++    ['media-hub', 'search.document.write', 'openvibe.search', []],
      // Plan T5 step 7: Tools posts one usage reading per ended tool job to Billing (POST /api/v1/usage).
      ['tools', 'billing.usage.record', 'openvibe.billing', []],
      // Plan T5 step 14: Network's own usage producers — AI (per model run), Events (per delivered event)