Create and test Java Cassandra app conversion to Cosmos NoSQL using GHC agent instructions.md

[sesmyrnov]

Create and test Java Cassandra app conversion to Cosmos NoSQL using GHC agent instructions.md

• possibly different instructions for Spring and Non-Spring Java app sources
• account for Cassandra SAI and/or Datastax SOLR different implementations and suggest alternative solutions with Cosmos NoSQL and/or AI search
• suggest data migration/sync options using Spark and dual-wrtite..

[TheovanKraay]

Submitted PR: github/awesome-copilot#451