Enhance tracing and refactor blob-related keyspaces

[das-Abroxas]

This PR combines two main lines of work:

1. Tracing and observability improvements across the API, operations, storage, and networking layers
2. A refactor of blob and S3 object state into dedicated blob-related keyspaces

Tracing And Observability

This part of the branch improves end-to-end visibility and debugging across the system.

• adds richer request spans and trace ID recording in the HTTP and S3 layers
• propagates distributed trace context through gossip messages and inbound operation handling
• instruments storage dispatch/worker loops, operation execution, DHT handling, QUIC streams, and connection management
• improves timeout and error logging around storage, gossip, replication, and networking paths
• cleans up older tracing stubs and aligns telemetry helpers across crates

Blob Keyspace Refactor

This part of the branch changes how blob and object state is modeled and stored.

• introduces dedicated blob keyspaces such as BLOB_LOCATIONS_KEYSPACE, BLOB_HEAD_KEYSPACE, BLOB_VERSIONS_KEYSPACE, and HASH_PATHS_INDEX_KEYSPACE
• adds new shared blob primitives and helpers including BlobHeadKey, BlobVersion, HashPathIndexKey, and head-transition utilities
• moves S3 object state management away from the previous S3-specific keyspaces and updates PUT, GET, HEAD, DELETE, multipart, and replication flows accordingly
• centralizes blob permission-path construction and alias/index updates
• persists reference-backed objects as blob versions and supports on-demand replication for them
• extends aruna-doctor to inspect and debug the new blob-related keyspaces

Supporting Changes

A few additional changes support the two themes above.

• reworks parts of the network stack around reusable QUIC connections, stream handling, and DHT/runtime plumbing
• updates tests and supporting helpers in multipart, replication, and blob flows to match the new storage model and tracing behavior