feat(upload): add programmatic Ingest service and file-upload skill

Introduce upload/ingest as the single domain entry for storing files,
writing w_uploads records, and maintaining incremental stats. Refactor
HTTP UploadFile and delete handlers to delegate to ingest, fix stats
decrement ordering on Remove, and document usage in the file-upload skill.

internal/apps/upload/ingest/remove.go

@@ -0,0 +1,43 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package ingest
+
+import (
+	"context"
+
+	uploadstats "github.com/Rain-kl/Wavelet/internal/apps/upload/stats"
+	"github.com/Rain-kl/Wavelet/internal/model"
+	"github.com/Rain-kl/Wavelet/internal/repository"
+)
+
+// Remove soft-deletes an upload and decrements incremental stats.
+func Remove(ctx context.Context, uploadID uint64) (model.Upload, error) {
+	upload, err := repository.GetActiveUploadByID(ctx, uploadID)
+	if err != nil {
+		return model.Upload{}, err
+	}
+	uploadstats.RecordUploadStatsRemove(ctx, &upload)
+	if err := repository.SoftDeleteUpload(ctx, &upload); err != nil {
+		return model.Upload{}, err
+	}
+	upload.Status = model.UploadStatusDeleted
+	return upload, nil
+}
+
+// RemoveOwned soft-deletes an upload owned by userID and decrements incremental stats.
+func RemoveOwned(ctx context.Context, userID, uploadID uint64) (model.Upload, error) {
+	upload, err := repository.GetActiveUploadByID(ctx, uploadID)
+	if err != nil {
+		return model.Upload{}, err
+	}
+	if upload.UserID != userID {
+		return model.Upload{}, ErrForbidden
+	}
+	uploadstats.RecordUploadStatsRemove(ctx, &upload)
+	if err := repository.SoftDeleteUpload(ctx, &upload); err != nil {
+		return model.Upload{}, err
+	}
+	upload.Status = model.UploadStatusDeleted
+	return upload, nil
+}