refactor: domain-first module restructuring
Rename all modules, packages, config sections, and infrastructure from internal codenames (mercury, pollux, castor, connect, agent.*) to domain-first names (didcomm, credentials, did, connections, etc.) following ADR 0001. Changes include: - Rename module directories from codenames to domain names - Rename SBT project IDs, artifact names, and dependency objects - Rename Scala packages throughout the codebase - Rename agent.* packages (walletapi, server, notification, vdr) - Move notification traits from core to API module - Align event.notification package to notifications - Rename config sections (pollux -> credentials, connect -> connections) - Rename env vars (POLLUX_DB_* -> CREDENTIALS_DB_*, etc.) - Rename SQL migration paths and Docker/Helm infrastructure - Remove unused re-export package.scala files - Remove stale codename build artifact directories - Clean up import aliases and comments referencing old names - Update .github/labeler.yml and CI workflow for new paths Co-Authored-By: Claude Opus 4.6 <[email protected]> Signed-off-by: Yurii Shynbuiev <[email protected]>