Migrate derivative to educe (#8125)

Fixes #7001.


  Mostly mechanical replacement of `derivative` attributes with `educe` ones.

### **Attribute Syntax Changes**

```rust
// Bounds: = "..." → (...)
#[derivative(Hash(bound = "E: EthSpec"))]
#[educe(Hash(bound(E: EthSpec)))]

// Ignore: = "ignore" → (ignore)
#[derivative(PartialEq = "ignore")]
#[educe(PartialEq(ignore))]

// Default values: value = "..." → expression = ...
#[derivative(Default(value = "ForkName::Base"))]
#[educe(Default(expression = ForkName::Base))]

// Methods: format_with/compare_with = "..." → method(...)
#[derivative(Debug(format_with = "fmt_peer_set_as_len"))]
#[educe(Debug(method(fmt_peer_set_as_len)))]

// Empty bounds: removed entirely, educe can infer appropriate bounds
#[derivative(Default(bound = ""))]
#[educe(Default)]

// Transparent debug: manual implementation (educe doesn't support it)
#[derivative(Debug = "transparent")]
// Replaced with manual Debug impl that delegates to inner field
```

**Note**: Some bounds use strings (`bound("E: EthSpec")`) for superstruct compatibility (`expected ','` errors).


Co-Authored-By: Javier Chávarri <javier.chavarri@gmail.com>

Co-Authored-By: Mac L <mjladson@pm.me>

Cargo.toml

@@ -128,11 +128,11 @@ context_deserialize_derive = { path = "consensus/context_deserialize/context_des
 criterion = "0.5"
 delay_map = "0.4"
 deposit_contract = { path = "common/deposit_contract" }
-derivative = "2"
 directory = { path = "common/directory" }
 dirs = "3"
 discv5 = { version = "0.10", features = ["libp2p"] }
 doppelganger_service = { path = "validator_client/doppelganger_service" }
+educe = "0.6"
 eip_3076 = { path = "common/eip_3076" }
 either = "1.9"
 environment = { path = "lighthouse/environment" }