Phase 1: storage + catalog layer

- storaged: object_store backend (LocalFileSystem), PUT/GET/DELETE/LIST endpoints
- shared: arrow_helpers with Parquet roundtrip + schema fingerprinting (2 tests)
- catalogd: in-memory registry with write-ahead manifest persistence to object storage
- catalogd: POST/GET /datasets, GET /datasets/by-name/{name}
- gateway: wires storaged + catalogd with shared object_store state
- Phase tracker updated: Phase 0 + Phase 1 gates passed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/catalogd/Cargo.toml

@@ -5,8 +5,13 @@ edition = "2024"
 
 [dependencies]
 shared = { path = "../shared" }
+storaged = { path = "../storaged" }
 tokio = { workspace = true }
 axum = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 tracing = { workspace = true }
+bytes = { workspace = true }
+chrono = { workspace = true }
+uuid = { workspace = true }
+object_store = { workspace = true }