fix(gateway): sync plugin override protocol artifacts

Regeneration-Prompt: |
  Rebase PR #48277 onto current origin/main without changing its intent: gateway-owned plugin subagent runs should be able to forward per-run provider and model overrides through the internal agent RPC, while admin-only gating stays in the gateway agent handler.

  After rebasing, keep the PR scoped to prep fallout instead of broad unrelated cleanup. Commit the generated Swift protocol models required by adding provider/model to AgentParams, add the required Unreleased changelog entry, and update the new commands/agent test fixture so the explicit openai/gpt-4.1-mini override is allowed under the current model allowlist rules. Do not fold in unrelated existing main-branch test failures.

apps/shared/OpenClawKit/Sources/OpenClawProtocol/GatewayModels.swift

@@ -515,6 +515,8 @@ public struct PollParams: Codable, Sendable {
 public struct AgentParams: Codable, Sendable {
     public let message: String
     public let agentid: String?
+    public let provider: String?
+    public let model: String?
     public let to: String?
     public let replyto: String?
     public let sessionid: String?
@@ -542,6 +544,8 @@ public struct AgentParams: Codable, Sendable {
     public init(
         message: String,
         agentid: String?,
+        provider: String?,
+        model: String?,
         to: String?,
         replyto: String?,
         sessionid: String?,
@@ -568,6 +572,8 @@ public struct AgentParams: Codable, Sendable {
     {
         self.message = message
         self.agentid = agentid
+        self.provider = provider
+        self.model = model
         self.to = to
         self.replyto = replyto
         self.sessionid = sessionid
@@ -596,6 +602,8 @@ public struct AgentParams: Codable, Sendable {
     private enum CodingKeys: String, CodingKey {
         case message
         case agentid = "agentId"
+        case provider
+        case model
         case to
         case replyto = "replyTo"
         case sessionid = "sessionId"