feat: ACP thread-bound agents (#23580)

* docs: add ACP thread-bound agents plan doc

* docs: expand ACP implementation specification

* feat(acp): route ACP sessions through core dispatch and lifecycle cleanup

* feat(acp): add /acp commands and Discord spawn gate

* ACP: add acpx runtime plugin backend

* fix(subagents): defer transient lifecycle errors before announce

* Agents: harden ACP sessions_spawn and tighten spawn guidance

* Agents: require explicit ACP target for runtime spawns

* docs: expand ACP control-plane implementation plan

* ACP: harden metadata seeding and spawn guidance

* ACP: centralize runtime control-plane manager and fail-closed dispatch

* ACP: harden runtime manager and unify spawn helpers

* Commands: route ACP sessions through ACP runtime in agent command

* ACP: require persisted metadata for runtime spawns

* Sessions: preserve ACP metadata when updating entries

* Plugins: harden ACP backend registry across loaders

* ACPX: make availability probe compatible with adapters

* E2E: add manual Discord ACP plain-language smoke script

* ACPX: preserve streamed spacing across Discord delivery

* Docs: add ACP Discord streaming strategy

* ACP: harden Discord stream buffering for thread replies

* ACP: reuse shared block reply pipeline for projector

* ACP: unify streaming config and adopt coalesceIdleMs

* Docs: add temporary ACP production hardening plan

* Docs: trim temporary ACP hardening plan goals

* Docs: gate ACP thread controls by backend capabilities

* ACP: add capability-gated runtime controls and /acp operator commands

* Docs: remove temporary ACP hardening plan

* ACP: fix spawn target validation and close cache cleanup

* ACP: harden runtime dispatch and recovery paths

* ACP: split ACP command/runtime internals and centralize policy

* ACP: harden runtime lifecycle, validation, and observability

* ACP: surface runtime and backend session IDs in thread bindings

* docs: add temp plan for binding-service migration

* ACP: migrate thread binding flows to SessionBindingService

* ACP: address review feedback and preserve prompt wording

* ACPX plugin: pin runtime dependency and prefer bundled CLI

* Discord: complete binding-service migration cleanup and restore ACP plan

* Docs: add standalone ACP agents guide

* ACP: route harness intents to thread-bound ACP sessions

* ACP: fix spawn thread routing and queue-owner stall

* ACP: harden startup reconciliation and command bypass handling

* ACP: fix dispatch bypass type narrowing

* ACP: align runtime metadata to agentSessionId

* ACP: normalize session identifier handling and labels

* ACP: mark thread banner session ids provisional until first reply

* ACP: stabilize session identity mapping and startup reconciliation

* ACP: add resolved session-id notices and cwd in thread intros

* Discord: prefix thread meta notices consistently

* Discord: unify ACP/thread meta notices with gear prefix

* Discord: split thread persona naming from meta formatting

* Extensions: bump acpx plugin dependency to 0.1.9

* Agents: gate ACP prompt guidance behind acp.enabled

* Docs: remove temp experiment plan docs

* Docs: scope streaming plan to holy grail refactor

* Docs: refactor ACP agents guide for human-first flow

* Docs/Skill: add ACP feature-flag guidance and direct acpx telephone-game flow

* Docs/Skill: add OpenCode and Pi to ACP harness lists

* Docs/Skill: align ACP harness list with current acpx registry

* Dev/Test: move ACP plain-language smoke script and mark as keep

* Docs/Skill: reorder ACP harness lists with Pi first

* ACP: split control-plane manager into core/types/utils modules

* Docs: refresh ACP thread-bound agents plan

* ACP: extract dispatch lane and split manager domains

* ACP: centralize binding context and remove reverse deps

* Infra: unify system message formatting

* ACP: centralize error boundaries and session id rendering

* ACP: enforce init concurrency cap and strict meta clear

* Tests: fix ACP dispatch binding mock typing

* Tests: fix Discord thread-binding mock drift and ACP request id

* ACP: gate slash bypass and persist cleared overrides

* ACPX: await pre-abort cancel before runTurn return

* Extension: pin acpx runtime dependency to 0.1.11

* Docs: add pinned acpx install strategy for ACP extension

* Extensions/acpx: enforce strict local pinned startup

* Extensions/acpx: tighten acp-router install guidance

* ACPX: retry runtime test temp-dir cleanup

* Extensions/acpx: require proactive ACPX repair for thread spawns

* Extensions/acpx: require restart offer after acpx reinstall

* extensions/acpx: remove workspace protocol devDependency

* extensions/acpx: bump pinned acpx to 0.1.13

* extensions/acpx: sync lockfile after dependency bump

* ACPX: make runtime spawn Windows-safe

* fix: align doctor-config-flow repair tests with default-account migration (#23580) (thanks @osolmaz)

src/discord/monitor/provider.test.ts

@@ -9,6 +9,7 @@ const {
   createDiscordNativeCommandMock,
   createNoopThreadBindingManagerMock,
   createThreadBindingManagerMock,
+  reconcileAcpThreadBindingsOnStartupMock,
   createdBindingManagers,
   listNativeCommandSpecsForConfigMock,
   listSkillCommandsForAgentsMock,
@@ -17,6 +18,8 @@ const {
   resolveDiscordAllowlistConfigMock,
   resolveNativeCommandsEnabledMock,
   resolveNativeSkillsEnabledMock,
+  resolveThreadBindingSessionTtlMsMock,
+  resolveThreadBindingsEnabledMock,
 } = vi.hoisted(() => {
   const createdBindingManagers: Array<{ stop: ReturnType<typeof vi.fn> }> = [];
   return {
@@ -33,6 +36,11 @@ const {
       createdBindingManagers.push(manager);
       return manager;
     }),
+    reconcileAcpThreadBindingsOnStartupMock: vi.fn(() => ({
+      checked: 0,
+      removed: 0,
+      staleSessionKeys: [],
+    })),
     createdBindingManagers,
     listNativeCommandSpecsForConfigMock: vi.fn(() => [{ name: "cmd" }]),
     listSkillCommandsForAgentsMock: vi.fn(() => []),
@@ -55,6 +63,8 @@ const {
     })),
     resolveNativeCommandsEnabledMock: vi.fn(() => true),
     resolveNativeSkillsEnabledMock: vi.fn(() => false),
+    resolveThreadBindingSessionTtlMsMock: vi.fn(() => undefined),
+    resolveThreadBindingsEnabledMock: vi.fn(() => true),
   };
 });
 
@@ -224,6 +234,9 @@ vi.mock("./rest-fetch.js", () => ({
 vi.mock("./thread-bindings.js", () => ({
   createNoopThreadBindingManager: createNoopThreadBindingManagerMock,
   createThreadBindingManager: createThreadBindingManagerMock,
+  reconcileAcpThreadBindingsOnStartup: reconcileAcpThreadBindingsOnStartupMock,
+  resolveThreadBindingSessionTtlMs: resolveThreadBindingSessionTtlMsMock,
+  resolveThreadBindingsEnabled: resolveThreadBindingsEnabledMock,
 }));
 
 describe("monitorDiscordProvider", () => {
@@ -252,6 +265,11 @@ describe("monitorDiscordProvider", () => {
     createDiscordNativeCommandMock.mockClear().mockReturnValue({ name: "mock-command" });
     createNoopThreadBindingManagerMock.mockClear();
     createThreadBindingManagerMock.mockClear();
+    reconcileAcpThreadBindingsOnStartupMock.mockClear().mockReturnValue({
+      checked: 0,
+      removed: 0,
+      staleSessionKeys: [],
+    });
     createdBindingManagers.length = 0;
     listNativeCommandSpecsForConfigMock.mockClear().mockReturnValue([{ name: "cmd" }]);
     listSkillCommandsForAgentsMock.mockClear().mockReturnValue([]);
@@ -265,6 +283,8 @@ describe("monitorDiscordProvider", () => {
     });
     resolveNativeCommandsEnabledMock.mockClear().mockReturnValue(true);
     resolveNativeSkillsEnabledMock.mockClear().mockReturnValue(false);
+    resolveThreadBindingSessionTtlMsMock.mockClear().mockReturnValue(undefined);
+    resolveThreadBindingsEnabledMock.mockClear().mockReturnValue(true);
   });
 
   it("stops thread bindings when startup fails before lifecycle begins", async () => {
@@ -296,6 +316,7 @@ describe("monitorDiscordProvider", () => {
     expect(monitorLifecycleMock).toHaveBeenCalledTimes(1);
     expect(createdBindingManagers).toHaveLength(1);
     expect(createdBindingManagers[0]?.stop).toHaveBeenCalledTimes(1);
+    expect(reconcileAcpThreadBindingsOnStartupMock).toHaveBeenCalledTimes(1);
   });
 
   it("captures gateway errors emitted before lifecycle wait starts", async () => {