Implements a concrete foundation for issue #15 (Community & User Reputation System):

• Added event-sourced reputation schema with moderation + appeals tables
• Added API contract for event ingestion, snapshots, moderation, and appeals
• Added phased implementation plan and success criteria

This is structured as a mergeable, production-oriented first milestone that unblocks incremental implementation and testing.

@algora-pbc /claim #15

Demo video

• https://github.com/aimqwest/gyroflow/releases/download/aimqwest-pr-demos-20260512/pr32-demo-v6.mp4