feat: implement NIP-09 (deletions) and NIP-11 (relay info)

NIP-11 (Relay Information Document):
- Serves relay metadata at GET / with Accept: application/nostr+json
- Returns name, description, supported NIPs, limitations
- CORS headers for browser compatibility

NIP-09 (Event Deletion):
- Kind 5 events delete events referenced in 'e' tags
- Only authors can delete their own events
- Soft delete (marks deleted=1)
- Records deletion in deletions table
- Works across all protocols (gRPC, Connect, WebSocket)

Fixed deletions schema:
- deleted_event_id as PRIMARY KEY (not deletion_event_id)
- Allows one deletion event to delete multiple events

3 new tests, 44 total tests passing

Supported NIPs now: 1, 9, 11

1 files changed, 11 insertions, 0 deletions

diff --git a/internal/handler/grpc/server.go b/internal/handler/grpc/server.go
index b65b527..b1ffd96 100644
--- a/internal/handler/grpc/server.go
+++ b/internal/handler/grpc/server.go
@@ -13,6 +13,7 @@ import (
 type EventStore interface {
         StoreEvent(context.Context, *storage.EventData) error
         QueryEvents(context.Context, []*pb.Filter, *storage.QueryOptions) ([]*pb.Event, error)
+        ProcessDeletion(context.Context, *pb.Event) error
 }
 
 type Server struct {
@@ -75,6 +76,16 @@ func (s *Server) PublishEvent(ctx context.Context, req *pb.PublishEventRequest)
                 return nil, fmt.Errorf("failed to store event: %w", err)
         }
 
+        if req.Event.Kind == 5 {
+                if err := s.store.ProcessDeletion(ctx, req.Event); err != nil {
+                        return &pb.PublishEventResponse{
+                                Accepted:      false,
+                                Message:       fmt.Sprintf("deletion processing failed: %v", err),
+                                CanonicalJson: canonicalJSON,
+                        }, nil
+                }
+        }
+
         s.subs.MatchAndFan(req.Event)
 
         return &pb.PublishEventResponse{