feat: persist participant-scoped proposal recovery

server/api/store_adapters.go

@@ -5,6 +5,7 @@ import (
 	"database/sql"
 	"time"
 
+	"github.com/cosmic-clash/cosmic-clash/server/domain"
 	"github.com/cosmic-clash/cosmic-clash/server/store"
 )
 
@@ -29,3 +30,13 @@ func AssignmentProviderFromStore(db *sql.DB) AssignmentProvider {
 		}, nil
 	}
 }
+
+type postgresProposalBackend struct{ db *sql.DB }
+
+func (p postgresProposalBackend) Get(ctx context.Context, playerID, proposalID string, now time.Time) (domain.Proposal, error) {
+	return store.GetProposal(ctx, p.db, playerID, proposalID, now)
+}
+
+func ProposalProviderFromStore(db *sql.DB) ProposalBackend {
+	return postgresProposalBackend{db: db}
+}