fix(auto-update): resolve cached version when installed as oh-my-openagent (#3257)

The auto-update-checker's version resolver hardcoded the canonical
oh-my-opencode package name in three read paths:

  1. INSTALLED_PACKAGE_JSON pointed only at
     cache/node_modules/oh-my-opencode/package.json
  2. findPackageJsonUp() rejected any walked-up package.json whose name
     did not equal PACKAGE_NAME
  3. getLocalDevPath() only matched file:// plugin entries whose path
     contained the canonical name

The publish pipeline ships the same code under two npm package names
(oh-my-opencode canonical, oh-my-openagent alias). Users who add
"oh-my-openagent" to their opencode config end up with
node_modules/oh-my-openagent/package.json, so every read path above
silently missed the installed version and the startup toast fell back
to "unknown".

Introduce ACCEPTED_PACKAGE_NAMES + INSTALLED_PACKAGE_JSON_CANDIDATES in
constants.ts and teach the three readers to accept both names. Writes
are untouched (sync-package-json, pinned-version-updater, cache
invalidation) because the auto-update-checker still owns its own cache
workspace and writes to the canonical name there.

Tests: 54 auto-update-checker tests pass (4 new), full 4444-test suite
passes, tsc clean. New tests cover both install paths, the walk-up
resolver, and the priority order when both candidates exist.

Closes #3257

src/hooks/auto-update-checker/checker/cached-version.test.ts

@@ -0,0 +1,80 @@
+import { afterEach, beforeEach, describe, expect, it, mock } from "bun:test"
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs"
+import { tmpdir } from "node:os"
+import { join } from "node:path"
+
+// Hold mutable mock state so beforeEach can swap the cache root for each test.
+const mockState: { candidates: string[] } = { candidates: [] }
+
+mock.module("../constants", () => ({
+  INSTALLED_PACKAGE_JSON_CANDIDATES: new Proxy([], {
+    get(_, prop) {
+      const current = mockState.candidates
+      // Forward array methods/properties to the mutable candidates list
+      // so getCachedVersion's `for (... of ...)` sees fresh data per test.
+      const value = (current as unknown as Record<PropertyKey, unknown>)[prop]
+      if (typeof value === "function") {
+        return (value as (...args: unknown[]) => unknown).bind(current)
+      }
+      return value
+    },
+  }),
+}))
+
+mock.module("./package-json-locator", () => ({
+  findPackageJsonUp: () => null,
+}))
+
+import { getCachedVersion } from "./cached-version"
+
+describe("getCachedVersion (GH-3257)", () => {
+  let cacheRoot: string
+
+  beforeEach(() => {
+    cacheRoot = mkdtempSync(join(tmpdir(), "omo-cached-version-"))
+    mockState.candidates = [
+      join(cacheRoot, "node_modules", "oh-my-opencode", "package.json"),
+      join(cacheRoot, "node_modules", "oh-my-openagent", "package.json"),
+    ]
+  })
+
+  afterEach(() => {
+    rmSync(cacheRoot, { recursive: true, force: true })
+    mockState.candidates = []
+  })
+
+  it("returns the version when the package is installed under oh-my-opencode", () => {
+    const pkgDir = join(cacheRoot, "node_modules", "oh-my-opencode")
+    mkdirSync(pkgDir, { recursive: true })
+    writeFileSync(join(pkgDir, "package.json"), JSON.stringify({ name: "oh-my-opencode", version: "3.16.0" }))
+
+    expect(getCachedVersion()).toBe("3.16.0")
+  })
+
+  it("returns the version when the package is installed under oh-my-openagent", () => {
+    // GH-3257: npm users who install the aliased `oh-my-openagent` package get
+    // node_modules/oh-my-openagent/package.json, not the canonical oh-my-opencode
+    // path. The cached version resolver must check both.
+    const pkgDir = join(cacheRoot, "node_modules", "oh-my-openagent")
+    mkdirSync(pkgDir, { recursive: true })
+    writeFileSync(join(pkgDir, "package.json"), JSON.stringify({ name: "oh-my-openagent", version: "3.16.0" }))
+
+    expect(getCachedVersion()).toBe("3.16.0")
+  })
+
+  it("prefers oh-my-opencode when both are installed", () => {
+    const legacyDir = join(cacheRoot, "node_modules", "oh-my-opencode")
+    mkdirSync(legacyDir, { recursive: true })
+    writeFileSync(join(legacyDir, "package.json"), JSON.stringify({ name: "oh-my-opencode", version: "3.16.0" }))
+
+    const aliasDir = join(cacheRoot, "node_modules", "oh-my-openagent")
+    mkdirSync(aliasDir, { recursive: true })
+    writeFileSync(join(aliasDir, "package.json"), JSON.stringify({ name: "oh-my-openagent", version: "3.15.0" }))
+
+    expect(getCachedVersion()).toBe("3.16.0")
+  })
+
+  it("returns null when neither candidate exists and fallbacks find nothing", () => {
+    expect(getCachedVersion()).toBeNull()
+  })
+})