feat: wire durable assignments into API

server/api/store_adapters.go

@@ -0,0 +1,31 @@
+package api
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/cosmic-clash/cosmic-clash/server/store"
+)
+
+// AssignmentProviderFromStore adapts the durable player-scoped assignment
+// projection to the HTTP boundary. The store query filters expiry and binds
+// both match and player; the API still performs its response-shape checks.
+func AssignmentProviderFromStore(db *sql.DB) AssignmentProvider {
+	return func(ctx context.Context, playerID, matchID string, now time.Time) (AssignmentView, error) {
+		assignment, err := store.GetAssignment(ctx, db, playerID, matchID, now)
+		if err != nil {
+			return AssignmentView{}, err
+		}
+		return AssignmentView{
+			MatchID:           assignment.MatchID,
+			ServerID:          assignment.ServerID,
+			PlayerID:          assignment.PlayerID,
+			Slot:              assignment.Slot,
+			ExpiresAt:         assignment.ExpiresAt,
+			ProtocolVersion:   assignment.ProtocolVersion,
+			Transport:         assignment.Transport,
+			JoinAuthorisation: assignment.JoinAuthorisation,
+		}, nil
+	}
+}

server/api/store_adapters_test.go

@@ -0,0 +1,17 @@
+package api
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+func TestAssignmentProviderFromStorePreservesPlayerScopedRecoveryBoundary(t *testing.T) {
+	provider := AssignmentProviderFromStore(nil)
+	if provider == nil {
+		t.Fatal("store provider was not created")
+	}
+	if _, err := provider(context.Background(), "player-1", "match-1", time.Unix(1000, 0)); err == nil {
+		t.Fatal("nil store was treated as an available assignment source")
+	}
+}