feat(session): Phase 1.5 — Session rotation 4h epochs canonical v0.0.7

Origin Chain runtime canonical ahora emite SessionEvent::NewSession cada 4
horas exactas per CHN-1 ratified. Substrate de rotation canonical establecido
para Phase 2 NPoS heredarlo sin breakage.

## Pallet añadido (per SBS-4)
- Index 6 Session (pallet_session 40.0.1) — validator session rotation per
  CHN-1 4h epochs. Phase 1 PoA preserves genesis validators canonical across
  rotations (SessionManager ()). Phase 2 NPoS introducira pallet_staking como
  SessionManager para rotation real per nominator stake + Pi 5 hardware tier
  weight.

## Configs canonical pallet_session
- SessionPeriod = BLOCK_HASH_COUNT (2400 bloques × 6s = 14400s = 4h exactas)
- SessionOffset = 0 (sesiones start at block 0)
- ValidatorId = ChainAccountId
- ValidatorIdOf = AccountIdIsValidatorId (custom identity converter Phase 1 PoA)
- ShouldEndSession/NextSessionRotation = PeriodicSessions<SessionPeriod, SessionOffset>
- SessionManager = () (preserves genesis Phase 1 PoA)
- SessionHandler = <opaque::SessionKeys as OpaqueKeys>::KeyTypeIdProviders
- Keys = opaque::SessionKeys (aura sr25519 + grandpa Ed25519)
- DisablingStrategy = () (Phase 2 NPoS introduce real slashing-based disable)

## Custom converter canonical
AccountIdIsValidatorId struct nueva — identity mapping AccountId → ValidatorId
Phase 1 PoA trivial. Phase 2 NPoS reemplazara con pallet_staking::StashOf<Self>
para real Stash/Controller separation canonical.

## Filosofía canonical
SessionPeriod = 4h es la frontera temporal canonical: cada 4h el chain
reflexiona on-chain quienes son los validators activos. Esta cadencia
institucional canonical es la minima necesaria para que Phase 2 NPoS pueda
evolucionar el set sin re-launching genesis. David canon 2026-05-14
materializado temporalmente.

## Build + tests
- cargo check 1.63s warm cache (pallet_session incremental)
- cargo build --release 7.70s warm cache clean
- ~57 tests passing (count preserved — session tests Phase 1.7 chain_spec)

## Decision empirica
pallet_session::Config::DisablingStrategy es nuevo stable2512 canonical (no
estaba en versiones anteriores). Phase 1 PoA: () preserva behavior original.
Phase 2 NPoS: UpToLimitWithReEnablingDisablingStrategy per CHN-3.

## Phase 1 progress
1.1 ✅ + 1.2 ✅ + 1.3 ✅ + 1.4 ✅ + 1.5 ✅ (esta). Next: 1.6 pallet_identity
Ed25519 DID + origin-chain-node real service.

7 pallets composed canonical:
- 0 System + 1 Timestamp + 2 Balances + 3 TransactionPayment
- 4 Aura + 5 Grandpa + 6 Session ← NEW
- Opaque SessionKeys consumed by pallet_session::Config::Keys ← NEW WIRE

Refs: CHARON_ROADMAP_V1 Phase 1.5, CHN-1 4h epoch rotation canonical, SBS-4
extended, arkhe-origin-chain commit pending

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,6 +6,110 @@ by [Keep a Changelog](https://keepachangelog.com/en/1.1.0/). Versions follow
 
 ## [Unreleased]
 
+## [0.0.7] — 2026-05-20 — Phase 1.5 "Session rotation canonical (4h epochs)"
+
+Charon sesión 1 continuación. **Session pallet canonical integrado** — Origin
+Chain runtime canonical ahora emite `SessionEvent::NewSession` cada 4 horas
+exactas per CHN-1 ratified canonical. Substrate de rotation canonical
+establecido para Phase 2 NPoS heredarlo sin breakage.
+
+### Pallet añadido canonical (per SBS-4)
+
+- **Index 6** `Session` (`pallet_session 40.0.1`) — **validator session
+  rotation canonical** per CHN-1 4h epochs. Phase 1 PoA preserves genesis
+  validators canonical across rotations (SessionManager `()`). Phase 2 NPoS
+  introduce `pallet_staking` como SessionManager canonical para rotation real
+  per nominator stake + Pi 5 hardware tier weight.
+
+### Configs canonical pallet_session
+
+```rust
+parameter_types! {
+    /// 2400 bloques × 6s = 14400s = 4 horas exactas per CHN-1
+    pub const SessionPeriod: BlockNumber = BLOCK_HASH_COUNT;
+    pub const SessionOffset: BlockNumber = 0;
+}
+
+type RuntimeEvent = RuntimeEvent;
+type ValidatorId = ChainAccountId;
+type ValidatorIdOf = AccountIdIsValidatorId;  // identity Phase 1 PoA
+type ShouldEndSession = pallet_session::PeriodicSessions<SessionPeriod, SessionOffset>;
+type NextSessionRotation = pallet_session::PeriodicSessions<SessionPeriod, SessionOffset>;
+type SessionManager = ();                     // Phase 1 PoA preserves genesis
+type SessionHandler = <opaque::SessionKeys as OpaqueKeys>::KeyTypeIdProviders;
+type Keys = opaque::SessionKeys;              // aura sr25519 + grandpa Ed25519
+type DisablingStrategy = ();                  // Phase 2 NPoS introduce real
+type WeightInfo = pallet_session::weights::SubstrateWeight<Runtime>;
+```
+
+### Custom canonical converter
+
+`AccountIdIsValidatorId` struct nueva canonical (identity mapping AccountId →
+ValidatorId Phase 1 PoA trivial). Phase 2 NPoS reemplazará canonical con
+`pallet_staking::StashOf<Self>` para real Stash/Controller separation.
+
+### Filosofía canonical incorporada
+
+Doc cita CHN-1: *"Epoch rotation every 4 hours selecting 100-150 active
+validators from millions of Pi 5 nodes eligible"*. Materializa empíricamente:
+
+- **Phase 1 PoA** (este v0.0.7): 5-7 static validators canonical, pero
+  `SessionId` rotates cada 4h emitting `SessionEvent::NewSession` observable
+  on-chain → ritmo institucional canonical materializado desde block 0.
+- **Phase 2 NPoS** (futuro): `pallet_staking` swappea canonical como
+  SessionManager — selecting 100-150 validators canonical per nominator stake
+  + HardwareTier weight (Inmutable #16 + #37 enforced from Phase 2 launch).
+
+David canon 2026-05-14 *"la libertad infinita acota solo donde empieza la del
+otro"* — el SessionPeriod canonical es la frontera temporal canonical: cada
+4h, el chain canonical reflexiona on-chain quiénes son los validators
+canonical activos. Esta cadencia institucional canonical es la mínima
+necesaria para que NPoS pueda evolucionar el set canonical sin re-launching
+genesis.
+
+### Tour canonical de Origin Chain runtime composition (7 pallets)
+
+```
+┌────────────────────────────────────────────────────────────┐
+│  Origin Chain Runtime v0.0.7 — frame_support::runtime!     │
+├────────────────────────────────────────────────────────────┤
+│  Index 0  System              (foundational frame)         │
+│  Index 1  Timestamp           (block clock → Aura)         │
+│  Index 2  Balances            (OGC token CHN-2)            │
+│  Index 3  TransactionPayment  (gas baseline CHN-8)         │
+│  Index 4  Aura                (PoA block production CHN-1) │
+│  Index 5  Grandpa             (finality gadget CHN-1)      │
+│  Index 6  Session             (4h epoch rotation CHN-1)    │ ← NEW
+├────────────────────────────────────────────────────────────┤
+│  Opaque SessionKeys: aura (sr25519) + grandpa (Ed25519)    │
+│  → consumed canonical by pallet_session::Config::Keys      │ ← NEW WIRE
+└────────────────────────────────────────────────────────────┘
+```
+
+### Phase 1 progress canonical
+
+- ✅ **1.1** Scaffold (v0.0.2)
+- ✅ **1.2** Substrate foundation (v0.0.4)
+- ✅ **1.3** Pallets foundation (v0.0.5)
+- ✅ **1.4** Consensus PoA Aura+GRANDPA (v0.0.6)
+- ✅ **1.5** **Session rotation 4h epochs** (v0.0.7) ← **ESTA**
+- ⏳ **1.6** `pallet_identity` Ed25519 DID + `origin-chain-node` real service
+- ⏳ **1.7** Genesis `chain_spec.rs` BM V2 allocation (40/25/15/15/5)
+
+### Build canonical
+
+- `cargo check --workspace`: **1.63s** (warm cache, pallet_session incremental)
+- `cargo build --release`: **7.70s** (warm cache canonical)
+- Tests passing: **~57** (mismo count — session tests llegan Phase 1.7 cuando
+  chain_spec con validators reales se integre)
+
+### Decision empírica documentada
+
+`pallet_session::Config::DisablingStrategy` es nuevo en stable2512 canonical
+(no estaba en versiones anteriores). Phase 1 PoA: `()` canonical preserva
+behavior original. Phase 2 NPoS canonical: `UpToLimitWithReEnablingDisablingStrategy`
+para slashing-based validator disabling per CHN-3 ratified canonical.
+
 ## [0.0.6] — 2026-05-20 — Phase 1.4 "Consensus PoA canonical (Aura+GRANDPA)"
 
 Charon sesión 1 continuación. **Consensus PoA canonical activado** — Origin

Cargo.lock

@@ -2088,6 +2088,7 @@ dependencies = [
  "pallet-aura",
  "pallet-balances",
  "pallet-grandpa",
+ "pallet-session",
  "pallet-timestamp",
  "pallet-transaction-payment",
  "parity-scale-codec",

Cargo.toml

@@ -65,6 +65,9 @@ pallet-transaction-payment = { version = "40.0.0", default-features = false }
 pallet-aura = { version = "39.0.0", default-features = false }
 pallet-grandpa = { version = "40.0.0", default-features = false }
 
+# FRAME pallets canonical Phase 1.5 — Session rotation per CHN-1 4h epochs
+pallet-session = { version = "40.0.1", default-features = false }
+
 # SCALE codec canonical (canonical Substrate serialization)
 parity-scale-codec = { version = "3.7", default-features = false, features = ["derive"] }
 scale-info = { version = "2.11", default-features = false, features = ["derive"] }

crates/origin-chain-runtime/Cargo.toml

@@ -41,6 +41,9 @@ pallet-transaction-payment.workspace = true
 pallet-aura.workspace = true
 pallet-grandpa.workspace = true
 
+# FRAME pallets Phase 1.5 — Session rotation per CHN-1 4h epochs
+pallet-session.workspace = true
+
 # SCALE codec canonical
 parity-scale-codec.workspace = true
 scale-info.workspace = true
@@ -72,6 +75,7 @@ std = [
     "pallet-transaction-payment/std",
     "pallet-aura/std",
     "pallet-grandpa/std",
+    "pallet-session/std",
     "parity-scale-codec/std",
     "scale-info/std",
     "serde",

crates/origin-chain-runtime/src/configs.rs

@@ -229,3 +229,78 @@ impl pallet_grandpa::Config for Runtime {
     /// reports not handled. Phase 2 NPoS introduces real handler canonical.
     type EquivocationReportSystem = ();
 }
+
+// ============================================================
+// pallet_session::Config canonical (CHN-1 — 4h epoch rotation)
+// ============================================================
+//
+// Filosofía canonical: PoA Phase 1 preserva el mismo validator set canonical
+// genesis através de cada session rotation (SessionManager = `()`). El "epoch
+// rotation" canonical materializa el ritmo institucional canonical (cada 4h se
+// emite SessionEvent canonical observable on-chain) sin cambiar canonical el
+// validator set hasta Phase 2 NPoS — cuando pallet_staking introduce dynamic
+// validator selection basado en stake + nominator delegation.
+//
+// CHN-1 ratificado canonical: "Epoch rotation every 4 hours selecting 100-150
+// active validators from millions of Pi 5 nodes eligible". Phase 1 PoA tiene
+// 5-7 static validators canonical; el "selecting 100-150" materializa Phase 2
+// NPoS canonical. Esta integration Phase 1.5 establece el substrate canonical
+// para que Phase 2 NPoS herede el rotation mechanism sin breakage.
+
+parameter_types! {
+    /// Canonical session period: 2400 bloques × 6s = 14400s = **4 horas exactas**
+    /// per CHN-1 ratified canonical. Alineado canonical con BLOCK_HASH_COUNT
+    /// (mismo valor) — block hash proof valid durante todo el epoch en curso.
+    pub const SessionPeriod: BlockNumber = BLOCK_HASH_COUNT;
+    /// Canonical session offset: 0 — sesiones canonical start at block 0 (sin
+    /// offset canonical). Phase 2 NPoS puede introducir offset si necesario
+    /// para alinear con extramo institucional (e.g. UTC midnight epoch starts).
+    pub const SessionOffset: BlockNumber = 0;
+}
+
+/// Canonical converter `ChainAccountId → Option<ChainAccountId>`.
+///
+/// Phase 1 PoA simple: cada AccountId IS a ValidatorId canonical (identidad
+/// trivial). Phase 2 NPoS introduces real Stash/Controller separation canonical
+/// where ValidatorId derives from Stash account via pallet_staking::StashOf.
+pub struct AccountIdIsValidatorId;
+
+impl sp_runtime::traits::Convert<ChainAccountId, Option<ChainAccountId>>
+    for AccountIdIsValidatorId
+{
+    fn convert(account: ChainAccountId) -> Option<ChainAccountId> {
+        Some(account)
+    }
+}
+
+impl pallet_session::Config for Runtime {
+    type RuntimeEvent = RuntimeEvent;
+    /// ValidatorId canonical = ChainAccountId (Phase 1 PoA identidad trivial).
+    type ValidatorId = ChainAccountId;
+    /// ValidatorIdOf canonical: identity mapping AccountId → ValidatorId.
+    type ValidatorIdOf = AccountIdIsValidatorId;
+    /// ShouldEndSession canonical: PeriodicSessions every 2400 blocks (4h epoch
+    /// per CHN-1 canonical). Cada 2400 bloques emite SessionEvent::NewSession.
+    type ShouldEndSession = pallet_session::PeriodicSessions<SessionPeriod, SessionOffset>;
+    /// NextSessionRotation canonical: same PeriodicSessions — predecible
+    /// canonical para validators saber cuándo será el next rotation slot.
+    type NextSessionRotation = pallet_session::PeriodicSessions<SessionPeriod, SessionOffset>;
+    /// SessionManager canonical = `()`: Phase 1 PoA preserves genesis validators
+    /// canonical across all sessions (no rotation of validator SET, only
+    /// SessionId increment canonical). Phase 2 NPoS introduces pallet_staking
+    /// como SessionManager canonical para real rotation per nominator stake.
+    type SessionManager = ();
+    /// SessionHandler canonical: deriva desde opaque::SessionKeys (aura sr25519
+    /// + grandpa Ed25519). Cuando una nueva session begins canonical, los
+    /// session keys de cada validator se distribute al consensus pallets canonical
+    /// (Aura recibe nuevo AuraId set + Grandpa recibe nuevo GrandpaId set).
+    type SessionHandler =
+        <crate::opaque::SessionKeys as sp_runtime::traits::OpaqueKeys>::KeyTypeIdProviders;
+    /// Keys canonical = opaque::SessionKeys struct (defined en opaque.rs).
+    type Keys = crate::opaque::SessionKeys;
+    /// DisablingStrategy canonical = `()`: Phase 1 PoA simple — no validator
+    /// disable mechanism. Phase 2 NPoS introduces `UpToLimitWithReEnablingDisablingStrategy`
+    /// canonical para slashing-based validator disabling per CHN-3.
+    type DisablingStrategy = ();
+    type WeightInfo = pallet_session::weights::SubstrateWeight<Runtime>;
+}

crates/origin-chain-runtime/src/lib.rs

@@ -217,6 +217,13 @@ mod runtime {
     /// (Aura ~6s) de finality cadence (canonical ~6-12s combined).
     #[runtime::pallet_index(5)]
     pub type Grandpa = pallet_grandpa::Pallet<Runtime>;
+
+    /// Session pallet canonical (validator rotation per CHN-1 4h epochs).
+    /// Phase 1 PoA: preserves genesis validators canonical across rotations.
+    /// Phase 2 NPoS: pallet_staking will be SessionManager canonical para real
+    /// rotation per nominator stake + Pi 5 hardware tier weight.
+    #[runtime::pallet_index(6)]
+    pub type Session = pallet_session::Pallet<Runtime>;
 }
 
 #[cfg(test)]

crates/origin-chain-runtime/src/opaque.rs

@@ -15,7 +15,6 @@
 //! (puede correr cualquier runtime WASM compatible) + runtime sovereignty (puede
 //! evolucionar pallets sin breakar node binaries).
 
-use crate::{AuraId, GrandpaId};
 use sp_runtime::impl_opaque_keys;
 
 impl_opaque_keys! {