fix: decouple replay oracle from snapshot cap

tools/evaluation/cmd/malt-eval-rq3-malt-worker/direct.go

@@ -534,6 +534,13 @@ func directFlatSnapshotChanges(state map[string]logicalFile) ([]gatewaytransport
 	if len(state) > maximumMALTSnapshotFiles {
 		return nil, fmt.Errorf("flat snapshot exceeds file bound")
 	}
+	return flatSnapshotChanges(state)
+}
+
+// flatSnapshotChanges projects every live file into the complete flat state.
+// Gateway request limits belong to directFlatSnapshotChanges: a history can
+// grow beyond its initial request size and still needs a complete final oracle.
+func flatSnapshotChanges(state map[string]logicalFile) ([]gatewaytransport.FlatPrefixChange, error) {
 	sentinel, err := flatSentinelEntry()
 	if err != nil {
 		return nil, err

tools/evaluation/cmd/malt-eval-rq3-malt-worker/flat.go

@@ -73,9 +73,10 @@ func (o *flatRootOracle) apply(ctx context.Context, changes []gatewaytransport.F
 }
 
 // fullFlatRoot reconstructs the complete post-image from live source files,
-// without using the mutation deltas or any Gateway response/state.
+// without using the mutation deltas or any Gateway response/state. Its local
+// reconstruction is independent of the single-request Gateway snapshot limit.
 func fullFlatRoot(ctx context.Context, files map[string]logicalFile) (cid.Cid, error) {
-	initial, err := directFlatSnapshotChanges(files)
+	initial, err := flatSnapshotChanges(files)
 	if err != nil {
 		return cid.Undef, err
 	}

tools/evaluation/cmd/malt-eval-rq3-malt-worker/flat_oracle_test.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+
+	clientcas "github.com/dewebprotocol/malt-client/internal/cas"
+	cid "github.com/ipfs/go-cid"
+)
+
+func TestFullFlatRootAcceptsStateBeyondSnapshotRequestLimit(t *testing.T) {
+	payload, err := clientcas.CIDForBlock(clientcas.Block{Codec: cid.Raw, Data: []byte("retained payload")})
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Model live disk-backed source metadata: the full oracle must use each
+	// retained payload CID, without loading file bodies or using Gateway state.
+	file := logicalFile{payload: payload, mode: 0o644}
+	files := make(map[string]logicalFile, maximumMALTSnapshotFiles+1)
+	var lastPath string
+	for i := 0; i <= maximumMALTSnapshotFiles; i++ {
+		lastPath = fmt.Sprintf("src/file-%06d.txt", i)
+		files[lastPath] = file
+	}
+	if _, err := directFlatSnapshotChanges(files); err == nil {
+		t.Fatal("oversized Gateway snapshot request was accepted")
+	}
+	changes, err := flatSnapshotChanges(files)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got, want := len(changes), 1+2*len(files); got != want {
+		t.Fatalf("full projection has %d bindings; want %d", got, want)
+	}
+	full, err := fullFlatRoot(t.Context(), files)
+	if err != nil {
+		t.Fatalf("full oracle for %d live files: %v", len(files), err)
+	}
+	if !full.Defined() {
+		t.Fatal("full oracle returned an undefined Root")
+	}
+
+	// The exact request boundary still accepts a complete initial snapshot.
+	// Incremental/full Root agreement is covered by the small-state oracle test;
+	// avoid a second large KZG construction in the default test suite.
+	delete(files, lastPath)
+	initial, err := directFlatSnapshotChanges(files)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got, want := len(initial), 1+2*len(files); got != want {
+		t.Fatalf("request projection has %d bindings; want %d", got, want)
+	}
+}