fix(#2823): auto-migrate legacy plugin name and warn users at startup

- logLegacyPluginStartupWarning now emits console.warn (visible to user,
  not just log file) when oh-my-opencode is detected in opencode.json
- Auto-migrates opencode.json plugin entry from oh-my-opencode to
  oh-my-openagent (with backup)
- plugin-config.ts: add console.warn when loading legacy config filename
- test: 10 tests covering migration, console output, edge cases

src/hooks/legacy-plugin-toast/hook.test.ts

@@ -0,0 +1,206 @@
+import { afterAll, beforeEach, describe, expect, it, mock } from "bun:test"
+import type { MigrationResult } from "./auto-migrate"
+
+const mockCheckForLegacyPluginEntry = mock(() => ({
+  hasLegacyEntry: false,
+  hasCanonicalEntry: false,
+  legacyEntries: [] as string[],
+}))
+
+const mockAutoMigrate = mock((): MigrationResult => ({
+  migrated: false,
+  from: null,
+  to: null,
+  configPath: null,
+}))
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const mockShowToast = mock((_arg: any) => Promise.resolve())
+const mockLog = mock(() => {})
+
+mock.module("../../shared/legacy-plugin-warning", () => ({
+  checkForLegacyPluginEntry: mockCheckForLegacyPluginEntry,
+}))
+
+mock.module("../../shared/logger", () => ({
+  log: mockLog,
+}))
+
+mock.module("./auto-migrate", () => ({
+  autoMigrateLegacyPluginEntry: mockAutoMigrate,
+}))
+
+afterAll(() => {
+  mock.restore()
+})
+
+function createMockCtx() {
+  return {
+    client: {
+      tui: { showToast: mockShowToast },
+    },
+    directory: "/tmp/test",
+  } as never
+}
+
+function createEvent(type: string, parentID?: string) {
+  return {
+    event: {
+      type,
+      properties: parentID ? { info: { parentID } } : { info: {} },
+    },
+  }
+}
+
+async function importFreshModule() {
+  return import(`./hook?t=${Date.now()}-${Math.random()}`)
+}
+
+describe("createLegacyPluginToastHook", () => {
+  beforeEach(() => {
+    mockCheckForLegacyPluginEntry.mockReset()
+    mockAutoMigrate.mockReset()
+    mockShowToast.mockReset()
+    mockLog.mockReset()
+
+    mockCheckForLegacyPluginEntry.mockReturnValue({
+      hasLegacyEntry: false,
+      hasCanonicalEntry: true,
+      legacyEntries: [],
+    })
+    mockAutoMigrate.mockReturnValue({ migrated: false, from: null, to: null, configPath: null })
+    mockShowToast.mockResolvedValue(undefined)
+  })
+
+  describe("#given no legacy entry exists", () => {
+    it("#then does not show a toast", async () => {
+      // given
+      const { createLegacyPluginToastHook } = await importFreshModule()
+      const hook = createLegacyPluginToastHook(createMockCtx())
+
+      // when
+      await hook.event(createEvent("session.created"))
+
+      // then
+      expect(mockShowToast).not.toHaveBeenCalled()
+    })
+  })
+
+  describe("#given legacy entry exists and migration succeeds", () => {
+    it("#then shows success toast", async () => {
+      // given
+      mockCheckForLegacyPluginEntry.mockReturnValue({
+        hasLegacyEntry: true,
+        hasCanonicalEntry: false,
+        legacyEntries: ["oh-my-opencode"],
+      })
+      mockAutoMigrate.mockReturnValue({
+        migrated: true,
+        from: "oh-my-opencode",
+        to: "oh-my-openagent",
+        configPath: "/tmp/opencode.json",
+      })
+      const { createLegacyPluginToastHook } = await importFreshModule()
+      const hook = createLegacyPluginToastHook(createMockCtx())
+
+      // when
+      await hook.event(createEvent("session.created"))
+
+      // then
+      expect(mockShowToast).toHaveBeenCalledTimes(1)
+      const toastArg = mockShowToast.mock.calls[0][0] as { body: { variant: string } }
+      expect(toastArg.body.variant).toBe("success")
+    })
+  })
+
+  describe("#given legacy entry exists but migration fails", () => {
+    it("#then shows warning toast", async () => {
+      // given
+      mockCheckForLegacyPluginEntry.mockReturnValue({
+        hasLegacyEntry: true,
+        hasCanonicalEntry: false,
+        legacyEntries: ["oh-my-opencode"],
+      })
+      mockAutoMigrate.mockReturnValue({
+        migrated: false,
+        from: null,
+        to: null,
+        configPath: "/tmp/opencode.json",
+      })
+      const { createLegacyPluginToastHook } = await importFreshModule()
+      const hook = createLegacyPluginToastHook(createMockCtx())
+
+      // when
+      await hook.event(createEvent("session.created"))
+
+      // then
+      expect(mockShowToast).toHaveBeenCalledTimes(1)
+      const toastArg2 = mockShowToast.mock.calls[0][0] as { body: { variant: string } }
+      expect(toastArg2.body.variant).toBe("warning")
+    })
+  })
+
+  describe("#given session.created fires twice", () => {
+    it("#then only fires once (once-guard)", async () => {
+      // given
+      mockCheckForLegacyPluginEntry.mockReturnValue({
+        hasLegacyEntry: true,
+        hasCanonicalEntry: false,
+        legacyEntries: ["oh-my-opencode"],
+      })
+      mockAutoMigrate.mockReturnValue({
+        migrated: true,
+        from: "oh-my-opencode",
+        to: "oh-my-openagent",
+        configPath: "/tmp/opencode.json",
+      })
+      const { createLegacyPluginToastHook } = await importFreshModule()
+      const hook = createLegacyPluginToastHook(createMockCtx())
+
+      // when
+      await hook.event(createEvent("session.created"))
+      await hook.event(createEvent("session.created"))
+
+      // then
+      expect(mockShowToast).toHaveBeenCalledTimes(1)
+    })
+  })
+
+  describe("#given a non-session.created event fires", () => {
+    it("#then does nothing", async () => {
+      // given
+      mockCheckForLegacyPluginEntry.mockReturnValue({
+        hasLegacyEntry: true,
+        hasCanonicalEntry: false,
+        legacyEntries: ["oh-my-opencode"],
+      })
+      const { createLegacyPluginToastHook } = await importFreshModule()
+      const hook = createLegacyPluginToastHook(createMockCtx())
+
+      // when
+      await hook.event(createEvent("session.deleted"))
+
+      // then
+      expect(mockCheckForLegacyPluginEntry).not.toHaveBeenCalled()
+    })
+  })
+
+  describe("#given session.created from a subagent (has parentID)", () => {
+    it("#then skips the check", async () => {
+      // given
+      mockCheckForLegacyPluginEntry.mockReturnValue({
+        hasLegacyEntry: true,
+        hasCanonicalEntry: false,
+        legacyEntries: ["oh-my-opencode"],
+      })
+      const { createLegacyPluginToastHook } = await importFreshModule()
+      const hook = createLegacyPluginToastHook(createMockCtx())
+
+      // when
+      await hook.event(createEvent("session.created", "parent-session-id"))
+
+      // then
+      expect(mockCheckForLegacyPluginEntry).not.toHaveBeenCalled()
+    })
+  })
+})