feat: add StreamWeightActor with unanimousNoHold governance and tests

Assisted-by: Claude:claude-sonnet-4-6

Author: wjmelements

src/StreamWeightActor.sol

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+pragma solidity ^0.8.36;
+
+import {FVMRewards} from "./lib/FVMRewards.sol";
+import {DistributionKind, PendingOp, WeightRecord} from "./lib/FVMRewardTypes.sol";
+import {OwnersLibrary} from "./lib/Owners.sol";
+import {UnanimousGovernance} from "./lib/UnanimousGovernance.sol";
+import {IsASafe} from "./lib/IsASafe.sol";
+
+contract StreamWeightActor is UnanimousGovernance {
+    using IsASafe for address;
+    using OwnersLibrary for address;
+
+    constructor(address owner1, address owner2) {
+        owner1.isProbablyASafe();
+        owner2.isProbablyASafe();
+
+        owner1.addOwner();
+        owner2.addOwner();
+    }
+
+    function registerStream(
+        uint64 id,
+        WeightRecord calldata record,
+        DistributionKind kind,
+        address writer,
+        uint64 activationEpoch
+    ) external unanimousNoHold(keccak256(msg.data)) {
+        // hold enforced in f02
+        FVMRewards.registerStream(id, record, kind, writer, activationEpoch);
+    }
+
+    function removeStream(uint64 id) external unanimousNoHold(keccak256(msg.data)) {
+        // hold enforced in f02
+        FVMRewards.removeStream(id);
+    }
+
+    function setWeightRecords(uint64[] memory ids, WeightRecord[] calldata records)
+        external
+        unanimousNoHold(keccak256(msg.data))
+    {
+        // hold enforced in f02
+        FVMRewards.setWeightRecords(ids, records);
+    }
+
+    function setDistribution(uint64 id, DistributionKind kind, address writer)
+        external
+        unanimousNoHold(keccak256(msg.data))
+    {
+        // hold enforced in f02
+        FVMRewards.setDistribution(id, kind, writer);
+    }
+
+    function cancelPending(uint64 id, PendingOp op) external {
+        // any owner can immediately cancel any pending operation
+        require(msg.sender.isOwner());
+        FVMRewards.cancelPending(id, op);
+    }
+
+    function replaceOwner(address prevOwner, address newOwner) external unanimousNoHold(keccak256(msg.data)) {
+        newOwner.isProbablyASafe();
+        prevOwner.removeOwner();
+        newOwner.addOwner();
+    }
+}

src/lib/UnanimousGovernance.sol

@@ -64,6 +64,34 @@ contract UnanimousGovernance {
         }
     }
 
+    modifier unanimousNoHold(bytes32 taskId) {
+        PendingTaskInfo storage taskInfo = PendingTaskLibrary.getTasksSlot()[taskId];
+        PendingTask memory loaded = taskInfo.task;
+        OwnerSet allOwners = OwnersLibrary.getAllOwners();
+
+        // approve
+        require(msg.sender.isOwner(), NotOwner(msg.sender));
+        OwnerSet ownerBit = msg.sender.asOwnerSet();
+        if (loaded.modified == UNSUBMITTED) {
+            emit Submitted(taskId);
+        } else {
+            require(loaded.approvals & ownerBit == EMPTY_SET, AlreadyApproved());
+        }
+        loaded.modified = currentEpoch();
+        loaded.approvals = loaded.approvals | ownerBit;
+
+        // store result
+        emit Approved(taskId, msg.sender);
+        if (loaded.approvals & allOwners == allOwners) {
+            delete taskInfo.task;
+            // execute now
+            _;
+        } else {
+            // wait
+            taskInfo.task = loaded;
+        }
+    }
+
     /// @param taskId The identifier of the pending task to reject
     function _veto(bytes32 taskId) internal {
         // load