graphql-alt: MovePackage.packageAt

## Description

Support fetching a different version of an existing package, similar to
`Object.objectAt`, but navigating the package versioning scheme (where
packages have their own IDs, but share an "original ID".

## Test plan

New E2E tests:

```
sui$ cargo nextest run         \
  -p sui-indexer-alt-e2e-tests \
  -- graphql/packages/package_at
```

Author: amnn

crates/sui-indexer-alt-e2e-tests/tests/graphql/packages/package_at.move

@@ -0,0 +1,59 @@
+// Copyright (c) Mysten Labs, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+//# init --protocol-version 70 --accounts A --addresses P1=0x0 P2=0x0  P3=0x0 --simulator
+
+//# publish --upgradeable --sender A
+module P1::M {
+  public fun foo(): u64 { 42 }
+}
+
+//# upgrade --package P1 --upgrade-capability 1,1 --sender A
+module P2::M {
+  public fun foo(): u64 { 43 }
+}
+
+//# create-checkpoint
+
+//# upgrade --package P2 --upgrade-capability 1,1 --sender A
+module P3::M {
+  public fun foo(): u64 { 44 }
+}
+
+//# create-checkpoint
+
+//# run-graphql
+{ # Fetching packages as objects, to confirm their addresses and versions
+  p1: object(address: "@{obj_1_0}") {
+    address
+    version
+  }
+
+  p2: object(address: "@{obj_2_0}") {
+    address
+    version
+  }
+
+  p3: object(address: "@{obj_4_0}") {
+    address
+    version
+  }
+}
+
+//# run-graphql
+{
+  package(address: "@{obj_1_0}") {
+    address
+    version
+
+    initial: packageAt(version: 1) {
+      address
+      version
+    }
+
+    byCheckpoint: packageAt(checkpoint: 1) {
+      address
+      version
+    }
+  }
+}

crates/sui-indexer-alt-e2e-tests/tests/graphql/packages/package_at.snap

@@ -0,0 +1,71 @@
+---
+source: external-crates/move/crates/move-transactional-test-runner/src/framework.rs
+---
+processed 8 tasks
+
+init:
+A: object(0,0)
+
+task 1, lines 6-9:
+//# publish --upgradeable --sender A
+created: object(1,0), object(1,1)
+mutated: object(0,0)
+gas summary: computation_cost: 1000000, storage_cost: 5092000,  storage_rebate: 0, non_refundable_storage_fee: 0
+
+task 2, lines 11-14:
+//# upgrade --package P1 --upgrade-capability 1,1 --sender A
+created: object(2,0)
+mutated: object(0,0), object(1,1)
+gas summary: computation_cost: 1000000, storage_cost: 5092000,  storage_rebate: 2595780, non_refundable_storage_fee: 26220
+
+task 3, line 16:
+//# create-checkpoint
+Checkpoint created: 1
+
+task 4, lines 18-21:
+//# upgrade --package P2 --upgrade-capability 1,1 --sender A
+created: object(4,0)
+mutated: object(0,0), object(1,1)
+gas summary: computation_cost: 1000000, storage_cost: 5092000,  storage_rebate: 2595780, non_refundable_storage_fee: 26220
+
+task 5, line 23:
+//# create-checkpoint
+Checkpoint created: 2
+
+task 6, lines 25-41:
+//# run-graphql
+Response: {
+  "data": {
+    "p1": {
+      "address": "0x37c66e5033ffe07f458c76432c64848275451aaeb5d6d4420e14818318b93759",
+      "version": 1
+    },
+    "p2": {
+      "address": "0x57bf7d91755b58a6b82e41e490bd2f03e803d1c081fe85747312eb016f39314e",
+      "version": 2
+    },
+    "p3": {
+      "address": "0x50592365811b6d08409158a0917066ca3e822a4c49dd6ae4465150f8aeb9a1da",
+      "version": 3
+    }
+  }
+}
+
+task 7, lines 43-59:
+//# run-graphql
+Response: {
+  "data": {
+    "package": {
+      "address": "0x50592365811b6d08409158a0917066ca3e822a4c49dd6ae4465150f8aeb9a1da",
+      "version": 3,
+      "initial": {
+        "address": "0x37c66e5033ffe07f458c76432c64848275451aaeb5d6d4420e14818318b93759",
+        "version": 1
+      },
+      "byCheckpoint": {
+        "address": "0x57bf7d91755b58a6b82e41e490bd2f03e803d1c081fe85747312eb016f39314e",
+        "version": 2
+      }
+    }
+  }
+}

crates/sui-indexer-alt-graphql/schema.graphql

@@ -179,6 +179,12 @@ type MovePackage implements IAddressable & IObject {
 	"""
 	objectVersionsBefore(first: Int, after: String, last: Int, before: String, filter: VersionFilter): ObjectConnection!
 	"""
+	Fetch the package with the same original ID, at a different version, root version bound, or checkpoint.
+	
+	If no additional bound is provided, the latest version of this package is fetched at the latest checkpoint.
+	"""
+	packageAt(version: UInt53, checkpoint: UInt53): MovePackage
+	"""
 	The Base64-encoded BCS serialization of this package, as a `MovePackage`.
 	"""
 	packageBcs: Base64

crates/sui-indexer-alt-graphql/src/api/types/move_package.rs

@@ -133,6 +133,27 @@ impl MovePackage {
             .await
     }
 
+    /// Fetch the package with the same original ID, at a different version, root version bound, or checkpoint.
+    ///
+    /// If no additional bound is provided, the latest version of this package is fetched at the latest checkpoint.
+    async fn package_at(
+        &self,
+        ctx: &Context<'_>,
+        version: Option<UInt53>,
+        checkpoint: Option<UInt53>,
+    ) -> Result<Option<MovePackage>, RpcError<Error>> {
+        MovePackage::by_key(
+            ctx,
+            self.super_.super_.scope.clone(),
+            PackageKey {
+                address: self.super_.super_.address.into(),
+                version,
+                at_checkpoint: checkpoint,
+            },
+        )
+        .await
+    }
+
     /// The Base64-encoded BCS serialization of this package, as a `MovePackage`.
     async fn package_bcs(&self) -> Result<Option<Base64>, RpcError> {
         let bytes = bcs::to_bytes(&self.contents).context("Failed to serialize MovePackage")?;

crates/sui-indexer-alt-graphql/src/snapshots/sui_indexer_alt_graphql__tests__schema.graphql.snap

@@ -183,6 +183,12 @@ type MovePackage implements IAddressable & IObject {
 	"""
 	objectVersionsBefore(first: Int, after: String, last: Int, before: String, filter: VersionFilter): ObjectConnection!
 	"""
+	Fetch the package with the same original ID, at a different version, root version bound, or checkpoint.
+	
+	If no additional bound is provided, the latest version of this package is fetched at the latest checkpoint.
+	"""
+	packageAt(version: UInt53, checkpoint: UInt53): MovePackage
+	"""
 	The Base64-encoded BCS serialization of this package, as a `MovePackage`.
 	"""
 	packageBcs: Base64

crates/sui-indexer-alt-graphql/src/snapshots/sui_indexer_alt_graphql__tests__staging.graphql.snap

@@ -183,6 +183,12 @@ type MovePackage implements IAddressable & IObject {
 	"""
 	objectVersionsBefore(first: Int, after: String, last: Int, before: String, filter: VersionFilter): ObjectConnection!
 	"""
+	Fetch the package with the same original ID, at a different version, root version bound, or checkpoint.
+	
+	If no additional bound is provided, the latest version of this package is fetched at the latest checkpoint.
+	"""
+	packageAt(version: UInt53, checkpoint: UInt53): MovePackage
+	"""
 	The Base64-encoded BCS serialization of this package, as a `MovePackage`.
 	"""
 	packageBcs: Base64

crates/sui-indexer-alt-graphql/staging.graphql

@@ -179,6 +179,12 @@ type MovePackage implements IAddressable & IObject {
 	"""
 	objectVersionsBefore(first: Int, after: String, last: Int, before: String, filter: VersionFilter): ObjectConnection!
 	"""
+	Fetch the package with the same original ID, at a different version, root version bound, or checkpoint.
+	
+	If no additional bound is provided, the latest version of this package is fetched at the latest checkpoint.
+	"""
+	packageAt(version: UInt53, checkpoint: UInt53): MovePackage
+	"""
 	The Base64-encoded BCS serialization of this package, as a `MovePackage`.
 	"""
 	packageBcs: Base64