Add Blossom package with core functionalities for blob storage and authorization

- Introduced the Blossom package, implementing essential features for handling blob storage, including upload, retrieval, and deletion of blobs.
- Added authorization mechanisms for secure access to blob operations, validating authorization events based on Nostr standards.
- Implemented various HTTP handlers for managing blob interactions, including GET, HEAD, PUT, and DELETE requests.
- Developed utility functions for SHA256 hash calculations, MIME type detection, and range request handling.
- Established a storage layer using Badger database for efficient blob data management and metadata storage.
- Included placeholder implementations for media optimization and payment handling, setting the groundwork for future enhancements.
- Documented the new functionalities and usage patterns in the codebase for better maintainability and understanding.

pkg/blossom/media.go

@@ -0,0 +1,19 @@
+package blossom
+
+// OptimizeMedia optimizes media content (BUD-05)
+// This is a placeholder implementation - actual optimization would use
+// libraries like image processing, video encoding, etc.
+func OptimizeMedia(data []byte, mimeType string) (optimizedData []byte, optimizedMimeType string) {
+	// For now, just return the original data unchanged
+	// In a real implementation, this would:
+	// - Resize images to optimal dimensions
+	// - Compress images (JPEG quality, PNG optimization)
+	// - Convert formats if beneficial
+	// - Optimize video encoding
+	// - etc.
+	
+	optimizedData = data
+	optimizedMimeType = mimeType
+	return
+}
+