feat: add LIP-118 reward caller support

[rickstaa]

What

Client support for LIP-118: an orchestrator authorizes a separate low-privilege account to call reward() on its behalf so the stake-holding account can stay offline. Contracts shipped in livepeer/protocol#648 (live on Arbitrum One); subgraph and explorer already support it.

Usage

1. On a node holding the orchestrator key, run "Set reward caller" in livepeer_cli (needs -enableCliTxRoutes), or set it from the explorer.
2. Restart the node with the caller account's keystore and -ethOrchAddr <orchestrator>. No new flag: the node reads transcoderToRewardCaller(orchestrator) and takes the delegated path when it matches its own account.

Changes

• eth: SetRewardCaller / GetRewardCaller / RewardForTranscoder; Reward and RewardForTranscoder share the pool-hint computation, always keyed on the orchestrator. RewardService targets the orchestrator and re-checks authorization each round (CheckRewardCaller), so a revoked caller gets a clear error instead of a revert.
• starter: fails at startup when -reward is set on an account that is neither the orchestrator nor its reward caller (auto mode warns and stays off); service URI is read under -ethOrchAddr; -ethOrchAddr is validated.
• server: /setRewardCaller, /rewardCaller; /reward and /orchestratorInfo are orchestrator-aware. /activateOrchestrator, /setOrchestratorConfig, /setRewardCaller are rejected on a non-orchestrator account, because ServiceRegistry.setServiceURI and setRewardCaller have no caller check and would silently write to the wrong key.
• livepeer_cli: "Set reward caller" action (shows current, offers unset).

Verification

Bindings verified against the deployed Arbitrum One BondingManager (selectors dispatch; existing on-chain reward-caller pair reads back correctly); regenerating from the unmodified ABI reproduces the committed file byte-for-byte. Unit tests cover own/authorized/unauthorized/revoked/lookup-error paths, set/unset, and the account guard. Not covered: end-to-end devnet run of set → restart → reward → revoke.

[Copilot]

Pull request overview

Adds go-livepeer client, server, and CLI support for LIP-118 “reward caller” delegation, enabling an orchestrator to authorize a separate low-privilege wallet to call reward() on its behalf (keeping the stake-holding wallet cold).

Changes:

• Extend contract bindings + eth client APIs to set/get a reward caller and call reward on behalf of a transcoder.
• Make reward execution and CLI endpoints orchestrator-aware when running on a delegated (reward caller) wallet, including startup authorization checks and correct service URI lookup.
• Add server + eth unit tests covering authorized/unauthorized/revoked and delegated-wallet behaviors, plus CLI wizard action to set/unset the reward caller.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
server/webserver.go	Wires new CLI HTTP endpoints for reward caller management and routes /reward through server instance.
server/handlers.go	Adds delegated-wallet detection/guard, reward-caller endpoints, and orchestrator-aware /reward + /orchestratorInfo.
server/handlers_test.go	Adds coverage for delegated wallet behavior and reward caller set/unset; updates reward handler test wiring.
eth/stubclient.go	Extends mock/stub eth clients for reward caller and delegated reward calls.
eth/rewardservice.go	Makes reward service operate on an orchestrator address (delegated path) with per-round authorization re-check.
eth/rewardservice_test.go	Adds tests for delegated reward caller paths, revocation, and lookup errors.
eth/contracts/bondingManager.go	Regenerates/adds ABI bindings for LIP-118 methods and events.
eth/client.go	Adds SetRewardCaller/GetRewardCaller/RewardForTranscoder and refactors reward hint computation to be transcoder-keyed.
cmd/livepeer/starter/starter.go	Adds reward authorization check at startup (reward-gated) and service URI lookup keyed on orchestrator address when delegated.
cmd/livepeer/starter/starter_test.go	Updates tests for updated getServiceURI() signature.
cmd/livepeer_cli/wizard_transcoder.go	Adds interactive “Set reward caller” flow (set/unset) to the transcoder wizard.
cmd/livepeer_cli/livepeer_cli.go	Exposes the new wizard action in CLI options.
CHANGELOG_PENDING.md	Adds changelog entry for LIP-118 reward caller support.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[codecov]

Codecov Report

❌ Patch coverage is 27.21713% with 238 lines in your changes missing coverage. Please review.
✅ Project coverage is 35.49507%. Comparing base (176aa41) to head (7b75cde).

Files with missing lines	Patch %	Lines
eth/contracts/bondingManager.go	0.00000%	106 Missing ⚠️
cmd/livepeer_cli/wizard_transcoder.go	0.00000%	40 Missing ⚠️
cmd/livepeer/starter/starter.go	2.50000%	39 Missing ⚠️
server/handlers.go	72.22222%	16 Missing and 4 partials ⚠️
eth/stubclient.go	27.27273%	16 Missing ⚠️
eth/client.go	0.00000%	11 Missing ⚠️
eth/rewardservice.go	81.81818%	5 Missing and 1 partial ⚠️

Additional details and impacted files

@@                 Coverage Diff                 @@
##              master       #4011         +/-   ##
===================================================
- Coverage   35.53708%   35.49507%   -0.04201%     
===================================================
  Files            174         174                 
  Lines          45226       45519        +293     
===================================================
+ Hits           16072       16157         +85     
- Misses         27880       28081        +201     
- Partials        1274        1281          +7     

Files with missing lines	Coverage Δ
cmd/livepeer_cli/livepeer_cli.go	0.00000% <ø> (ø)
server/webserver.go	85.57692% <100.00000%> (+0.28280%)	⬆️
eth/rewardservice.go	81.57895% <81.81818%> (+7.03350%)	⬆️
eth/client.go	4.58404% <0.00000%> (-0.07917%)	⬇️
eth/stubclient.go	15.68627% <27.27273%> (+1.15636%)	⬆️
server/handlers.go	57.33906% <72.22222%> (+0.82128%)	⬆️
cmd/livepeer/starter/starter.go	22.55685% <2.50000%> (-0.36632%)	⬇️
cmd/livepeer_cli/wizard_transcoder.go	0.00000% <0.00000%> (ø)
eth/contracts/bondingManager.go	0.00000% <0.00000%> (ø)

... and 6 files with indirect coverage changes

---

Continue to review full report in Codecov by Harness.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 176aa41...7b75cde. Read the comment docs.

Files with missing lines	Coverage Δ
cmd/livepeer_cli/livepeer_cli.go	0.00000% <ø> (ø)
server/webserver.go	85.57692% <100.00000%> (+0.28280%)	⬆️
eth/rewardservice.go	81.57895% <81.81818%> (+7.03350%)	⬆️
eth/client.go	4.58404% <0.00000%> (-0.07917%)	⬇️
eth/stubclient.go	15.68627% <27.27273%> (+1.15636%)	⬆️
server/handlers.go	57.33906% <72.22222%> (+0.82128%)	⬆️
cmd/livepeer/starter/starter.go	22.55685% <2.50000%> (-0.36632%)	⬇️
cmd/livepeer_cli/wizard_transcoder.go	0.00000% <0.00000%> (ø)
eth/contracts/bondingManager.go	0.00000% <0.00000%> (ø)

... and 6 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.