refactor: move Discord channel implementation to extensions/ (#45660)

* refactor: move Discord channel implementation to extensions/discord/src/

Move all Discord source files from src/discord/ to extensions/discord/src/,
following the extension migration pattern. Source files in src/discord/ are
replaced with re-export shims. Channel-plugin files from
src/channels/plugins/*/discord* are similarly moved and shimmed.

- Copy all .ts source files preserving subdirectory structure (monitor/, voice/)
- Move channel-plugin files (actions, normalize, onboarding, outbound, status-issues)
- Fix all relative imports to use correct paths from new location
- Create re-export shims at original locations for backward compatibility
- Delete test files from shim locations (tests live in extension now)
- Update tsconfig.plugin-sdk.dts.json rootDir from "src" to "." to accommodate
  extension files outside src/
- Update write-plugin-sdk-entry-dts.ts to match new declaration output paths

* fix: add importOriginal to thread-bindings session-meta mock for extensions test

* style: fix formatting in thread-bindings lifecycle test

extensions/discord/src/monitor/native-command.options.test.ts

@@ -0,0 +1,69 @@
+import { describe, expect, it } from "vitest";
+import { listNativeCommandSpecs } from "../../../../src/auto-reply/commands-registry.js";
+import type { OpenClawConfig, loadConfig } from "../../../../src/config/config.js";
+import { createDiscordNativeCommand } from "./native-command.js";
+import { createNoopThreadBindingManager } from "./thread-bindings.js";
+
+function createNativeCommand(name: string): ReturnType<typeof createDiscordNativeCommand> {
+  const command = listNativeCommandSpecs({ provider: "discord" }).find(
+    (entry) => entry.name === name,
+  );
+  if (!command) {
+    throw new Error(`missing native command: ${name}`);
+  }
+  const cfg = {} as ReturnType<typeof loadConfig>;
+  const discordConfig = {} as NonNullable<OpenClawConfig["channels"]>["discord"];
+  return createDiscordNativeCommand({
+    command,
+    cfg,
+    discordConfig,
+    accountId: "default",
+    sessionPrefix: "discord:slash",
+    ephemeralDefault: true,
+    threadBindings: createNoopThreadBindingManager("default"),
+  });
+}
+
+type CommandOption = NonNullable<ReturnType<typeof createDiscordNativeCommand>["options"]>[number];
+
+function findOption(
+  command: ReturnType<typeof createDiscordNativeCommand>,
+  name: string,
+): CommandOption | undefined {
+  return command.options?.find((entry) => entry.name === name);
+}
+
+function readAutocomplete(option: CommandOption | undefined): unknown {
+  if (!option || typeof option !== "object") {
+    return undefined;
+  }
+  return (option as { autocomplete?: unknown }).autocomplete;
+}
+
+function readChoices(option: CommandOption | undefined): unknown[] | undefined {
+  if (!option || typeof option !== "object") {
+    return undefined;
+  }
+  const value = (option as { choices?: unknown }).choices;
+  return Array.isArray(value) ? value : undefined;
+}
+
+describe("createDiscordNativeCommand option wiring", () => {
+  it("uses autocomplete for /acp action so inline action values are accepted", () => {
+    const command = createNativeCommand("acp");
+    const action = findOption(command, "action");
+
+    expect(action).toBeDefined();
+    expect(typeof readAutocomplete(action)).toBe("function");
+    expect(readChoices(action)).toBeUndefined();
+  });
+
+  it("keeps static choices for non-acp string action arguments", () => {
+    const command = createNativeCommand("voice");
+    const action = findOption(command, "action");
+
+    expect(action).toBeDefined();
+    expect(readAutocomplete(action)).toBeUndefined();
+    expect(readChoices(action)?.length).toBeGreaterThan(0);
+  });
+});