fix: forward session events to Staking pallet for era management

ValidatorManager now forwards session hooks to Staking pallet:
- new_session: Staking receives session changes to trigger era
- start_session: Staking can initialize era stakers
- end_session: Staking can finalize era rewards

This fixes the issue where staking era never started because
session events were not being forwarded to the Staking pallet.

pezkuwi/runtime/pezkuwichain/src/lib.rs

@@ -1457,6 +1457,7 @@ impl assigned_slots::Config for Runtime {
 impl validator_manager::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type PrivilegedOrigin = EnsureRoot<AccountId>;
+	type Staking = Staking;
 }
 
 parameter_types! {

pezkuwi/runtime/pezkuwichain/src/validator_manager.rs

@@ -43,6 +43,9 @@ pub mod pezpallet {
 
 		/// Privileged origin that can add or remove validators.
 		type PrivilegedOrigin: EnsureOrigin<<Self as pezframe_system::Config>::RuntimeOrigin>;
+
+		/// Staking pallet for forwarding session events
+		type Staking: pezpallet_session::SessionManager<Self::ValidatorId>;
 	}
 
 	#[pezpallet::event]
@@ -103,6 +106,9 @@ pub mod pezpallet {
 
 impl<T: Config> pezpallet_session::SessionManager<T::ValidatorId> for Pezpallet<T> {
 	fn new_session(new_index: SessionIndex) -> Option<Vec<T::ValidatorId>> {
+		// Forward to Staking pallet for era management
+		let _ = T::Staking::new_session(new_index);
+
 		if new_index <= 1 {
 			return None;
 		}
@@ -124,9 +130,15 @@ impl<T: Config> pezpallet_session::SessionManager<T::ValidatorId> for Pezpallet<
 		Some(validators)
 	}
 
-	fn end_session(_: SessionIndex) {}
+	fn end_session(end_index: SessionIndex) {
+		// Forward to Staking pallet
+		T::Staking::end_session(end_index);
+	}
 
-	fn start_session(_start_index: SessionIndex) {}
+	fn start_session(start_index: SessionIndex) {
+		// Forward to Staking pallet
+		T::Staking::start_session(start_index);
+	}
 }
 
 impl<T: Config> pezpallet_session::historical::SessionManager<T::ValidatorId, ()> for Pezpallet<T> {