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>

beacon_node/network/src/sync/batch.rs

@@ -1,5 +1,5 @@
 use beacon_chain::block_verification_types::RpcBlock;
-use derivative::Derivative;
+use educe::Educe;
 use lighthouse_network::PeerId;
 use lighthouse_network::rpc::methods::BlocksByRangeRequest;
 use lighthouse_network::rpc::methods::DataColumnsByRangeRequest;
@@ -78,8 +78,8 @@ pub enum BatchProcessingResult {
     NonFaultyFailure,
 }
 
-#[derive(Derivative)]
-#[derivative(Debug)]
+#[derive(Educe)]
+#[educe(Debug)]
 /// A segment of a chain.
 pub struct BatchInfo<E: EthSpec, B: BatchConfig, D: Hash> {
     /// Start slot of the batch.
@@ -97,7 +97,7 @@ pub struct BatchInfo<E: EthSpec, B: BatchConfig, D: Hash> {
     /// Whether this batch contains all blocks or all blocks and blobs.
     batch_type: ByRangeRequestType,
     /// Pin the generic
-    #[derivative(Debug = "ignore")]
+    #[educe(Debug(ignore))]
     marker: std::marker::PhantomData<(E, B)>,
 }