fix(auto-update): match both canonical and legacy plugin names in entry finder

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/hooks/auto-update-checker/checker/plugin-entry.test.ts

@@ -4,6 +4,7 @@ import * as fs from "node:fs"
 import * as os from "node:os"
 import * as path from "node:path"
 import { PACKAGE_NAME } from "../constants"
+import { LEGACY_PLUGIN_NAME, PLUGIN_NAME } from "../../../shared/plugin-identity"
 
 type PluginEntryResult = {
   entry: string
@@ -120,6 +121,64 @@ describe("findPluginEntry", () => {
     expect(pluginInfo?.pinnedVersion).toBe("3.5.2")
   })
 
+  test("finds preferred plugin entry", async () => {
+    // #given preferred plugin entry is configured
+    fs.writeFileSync(configPath, JSON.stringify({ plugin: [PLUGIN_NAME] }))
+
+    // #when plugin entry is detected
+    const execution = runFindPluginEntry(temporaryDirectory)
+
+    // #then preferred entry is returned
+    expect(execution.status).toBe(0)
+    const pluginInfo = JSON.parse(execution.stdout.trim()) as PluginEntryResult
+    expect(pluginInfo?.entry).toBe(PLUGIN_NAME)
+    expect(pluginInfo?.isPinned).toBe(false)
+    expect(pluginInfo?.pinnedVersion).toBeNull()
+  })
+
+  test("finds legacy plugin entry", async () => {
+    // #given legacy plugin entry is configured
+    fs.writeFileSync(configPath, JSON.stringify({ plugin: [LEGACY_PLUGIN_NAME] }))
+
+    // #when plugin entry is detected
+    const execution = runFindPluginEntry(temporaryDirectory)
+
+    // #then legacy entry is returned
+    expect(execution.status).toBe(0)
+    const pluginInfo = JSON.parse(execution.stdout.trim()) as PluginEntryResult
+    expect(pluginInfo?.entry).toBe(LEGACY_PLUGIN_NAME)
+    expect(pluginInfo?.isPinned).toBe(false)
+    expect(pluginInfo?.pinnedVersion).toBeNull()
+  })
+
+  test("finds preferred plugin entry with pinned version", async () => {
+    // #given preferred plugin entry includes semver version
+    fs.writeFileSync(configPath, JSON.stringify({ plugin: [`${PLUGIN_NAME}@3.15.0`] }))
+
+    // #when plugin entry is detected
+    const execution = runFindPluginEntry(temporaryDirectory)
+
+    // #then preferred versioned entry is returned
+    expect(execution.status).toBe(0)
+    const pluginInfo = JSON.parse(execution.stdout.trim()) as PluginEntryResult
+    expect(pluginInfo?.entry).toBe(`${PLUGIN_NAME}@3.15.0`)
+    expect(pluginInfo?.isPinned).toBe(true)
+    expect(pluginInfo?.pinnedVersion).toBe("3.15.0")
+  })
+
+  test("returns null for unrelated plugin entry", async () => {
+    // #given unrelated plugin entry is configured
+    fs.writeFileSync(configPath, JSON.stringify({ plugin: ["some-other-plugin"] }))
+
+    // #when plugin entry is detected
+    const execution = runFindPluginEntry(temporaryDirectory)
+
+    // #then no matching entry is returned
+    expect(execution.status).toBe(0)
+    const pluginInfo = JSON.parse(execution.stdout.trim()) as PluginEntryResult
+    expect(pluginInfo).toBeNull()
+  })
+
   test("reads user config from profile dir even when OPENCODE_CONFIG_DIR changes after import", async () => {
     // #given profile-specific user config after module import
     const profileConfigDir = path.join(temporaryDirectory, "profiles", "today")