[DIFF] Built-in blob/attachment storage — store large files alongside KV data

[ElioNeto]

Differentiator

Transparent blob storage: small values inline, large values auto-moved to dedicated blob storage.

Behavior

• Values < threshold (64KB): stored inline, fast reads
• Values > threshold: stored in /blobs/, content-addressed (sha256)
• Streaming reads via HTTP Range requests
• Blob GC during compaction

Impact

• Eliminates need for S3/MinIO in small/medium apps
• One less infrastructure dependency
• Unique among embedded KV stores

[ElioNeto]

Implemented in commit 0871d91.