build-haks now accepts --source-manifest <path>

When that flag is used, sow-tools:
- collects only the assets referenced by that manifest subset
- skips full-project chunk planning for the per-archive run
- reconstructs just the requested archive chunks from the manifest

internal/app/app.go

@@ -179,9 +179,10 @@ func runBuildModule(ctx context) error {
 }
 
 type buildHAKOptions struct {
-	filteredHAKs []string
+	filteredHAKs     []string
 	filteredArchives []string
-	planOnly     bool
+	sourceManifest  string
+	planOnly        bool
 }
 
 func runBuildHAKs(ctx context) error {
@@ -207,8 +208,9 @@ func runBuildHAKs(ctx context) error {
 		result, err = pipeline.PlanHAKsWithProgress(p, progress)
 	} else {
 		result, err = pipeline.BuildHAKsWithOptions(p, pipeline.BuildHAKOptions{
-			Progress:       progress,
-			ArchiveNames:   opts.filteredArchives,
+			Progress:           progress,
+			ArchiveNames:       opts.filteredArchives,
+			SourceManifestPath: opts.sourceManifest,
 		})
 	}
 	if err != nil {
@@ -234,7 +236,7 @@ func parseBuildHAKArgs(args []string) (buildHAKOptions, error) {
 		arg := args[index]
 		switch arg {
 		case "-h", "--help":
-			return opts, errors.New("usage: build-haks [--hak <hak-name> ...] [--archive <archive-name> ...] [--plan-only]")
+			return opts, errors.New("usage: build-haks [--hak <hak-name> ...] [--archive <archive-name> ...] [--source-manifest <path>] [--plan-only]")
 		case "--hak":
 			index++
 			if index >= len(args) {
@@ -249,6 +251,12 @@ func parseBuildHAKArgs(args []string) (buildHAKOptions, error) {
 			opts.filteredArchives = append(opts.filteredArchives, args[index])
 		case "--plan-only":
 			opts.planOnly = true
+		case "--source-manifest":
+			index++
+			if index >= len(args) {
+				return opts, errors.New("--source-manifest requires a value")
+			}
+			opts.sourceManifest = args[index]
 		default:
 			if value, ok := parseInlineFlagValue(arg, "--hak"); ok {
 				opts.filteredHAKs = append(opts.filteredHAKs, value)
@@ -258,6 +266,10 @@ func parseBuildHAKArgs(args []string) (buildHAKOptions, error) {
 				opts.filteredArchives = append(opts.filteredArchives, value)
 				continue
 			}
+			if value, ok := parseInlineFlagValue(arg, "--source-manifest"); ok {
+				opts.sourceManifest = value
+				continue
+			}
 			return opts, fmt.Errorf("unknown build-haks argument %q", arg)
 		}
 	}