Implement restore planning for the restore subcommand

internal/app/restore.go

@@ -13,6 +13,7 @@ import (
 
 var newObjectStoreFromConfigFn = storage.NewObjectStoreFromConfig
 var discoverRemoteCurrentStateFn = discoverRemoteCurrentState
+var buildRestorePlanFn = buildRestorePlan
 
 // Restore validates restore CLI/config inputs and storage preflight for future restore phases.
 func Restore(ctx context.Context, args []string, out io.Writer) error {
@@ -74,13 +75,32 @@ func Restore(ctx context.Context, args []string, out io.Writer) error {
 	if err != nil {
 		return fmt.Errorf("restore: %w", err)
 	}
-
-	// Phase 3 boundary: discovery is implemented; planning/execution is deferred.
-	_ = dryRun
-	_ = force
-	_ = includeAudio
+	plan, err := buildRestorePlanFn(ctx, cfg, current, objectStore, RestorePlanOptions{
+		IncludeAudio: includeAudio,
+		Force:        force,
+		DryRun:       dryRun,
+	})
+	if err != nil {
+		return fmt.Errorf("restore: %w", err)
+	}
+	if err := writeRestorePlan(out, current, plan, RestorePlanOptions{
+		IncludeAudio: includeAudio,
+		Force:        force,
+		DryRun:       dryRun,
+	}); err != nil {
+		return fmt.Errorf("restore: write plan output: %w", err)
+	}
+	if dryRun {
+		return nil
+	}
+	if plan.ConflictCount > 0 && !force {
+		return fmt.Errorf(
+			"restore: plan has %d conflicting path(s); rerun with --force or resolve local conflicts",
+			plan.ConflictCount,
+		)
+	}
 	return fmt.Errorf(
-		"restore: discovered remote current state for %s/%s (run %s); not yet implemented (phase 3: remote current-state discovery)",
+		"restore: planned remote restore for %s/%s (run %s); not yet implemented (phase 4: restore execution)",
 		current.Campaign,
 		current.SessionID,
 		current.RunID,