fix: rename .claude.json to .openclaude.json with legacy fallback (#582)

* fix: rename .claude.json to .openclaude.json with legacy fallback

Rename the global config file from ~/.claude.json to ~/.openclaude.json,
following the same migration pattern as the config directory
(~/.claude → ~/.openclaude).

- getGlobalClaudeFile() now prefers .openclaude.json; falls back to
  .claude.json only if the legacy file exists and the new one does not
- Add .openclaude.json to filesystem permissions allowlist (keep
  .claude.json for legacy file protection)
- Update all comment/string references from ~/.claude.json to
  ~/.openclaude.json across 12 files

New installs get .openclaude.json from the start. Existing users
continue using .claude.json until they rename it (or a future explicit
migration).

* test: add unit tests for getGlobalClaudeFile migration branches

Covers the three cases:
- new install (neither file exists) → .openclaude.json
- existing user (only legacy .claude.json exists) → .claude.json
- migrated user (both files exist) → .openclaude.json

---------

Co-authored-by: Zartris <14197299+Zartris@users.noreply.github.com>

src/utils/env.test.ts

@@ -0,0 +1,62 @@
+import { afterEach, beforeEach, expect, test } from 'bun:test'
+import { mkdtempSync, rmSync, writeFileSync } from 'fs'
+import { tmpdir } from 'os'
+import { join } from 'path'
+
+const originalEnv = {
+  CLAUDE_CONFIG_DIR: process.env.CLAUDE_CONFIG_DIR,
+  CLAUDE_CODE_CUSTOM_OAUTH_URL: process.env.CLAUDE_CODE_CUSTOM_OAUTH_URL,
+  USER_TYPE: process.env.USER_TYPE,
+}
+
+let tempDir: string
+
+beforeEach(() => {
+  tempDir = mkdtempSync(join(tmpdir(), 'openclaude-env-test-'))
+  process.env.CLAUDE_CONFIG_DIR = tempDir
+  delete process.env.CLAUDE_CODE_CUSTOM_OAUTH_URL
+  delete process.env.USER_TYPE
+})
+
+afterEach(() => {
+  rmSync(tempDir, { recursive: true, force: true })
+  if (originalEnv.CLAUDE_CONFIG_DIR === undefined) {
+    delete process.env.CLAUDE_CONFIG_DIR
+  } else {
+    process.env.CLAUDE_CONFIG_DIR = originalEnv.CLAUDE_CONFIG_DIR
+  }
+  if (originalEnv.CLAUDE_CODE_CUSTOM_OAUTH_URL === undefined) {
+    delete process.env.CLAUDE_CODE_CUSTOM_OAUTH_URL
+  } else {
+    process.env.CLAUDE_CODE_CUSTOM_OAUTH_URL = originalEnv.CLAUDE_CODE_CUSTOM_OAUTH_URL
+  }
+  if (originalEnv.USER_TYPE === undefined) {
+    delete process.env.USER_TYPE
+  } else {
+    process.env.USER_TYPE = originalEnv.USER_TYPE
+  }
+})
+
+async function importFreshEnvModule() {
+  return import(`./env.js?ts=${Date.now()}-${Math.random()}`)
+}
+
+// getGlobalClaudeFile — three migration branches
+
+test('getGlobalClaudeFile: new install returns .openclaude.json when neither file exists', async () => {
+  const { getGlobalClaudeFile } = await importFreshEnvModule()
+  expect(getGlobalClaudeFile()).toBe(join(tempDir, '.openclaude.json'))
+})
+
+test('getGlobalClaudeFile: existing user keeps .claude.json when only legacy file exists', async () => {
+  writeFileSync(join(tempDir, '.claude.json'), '{}')
+  const { getGlobalClaudeFile } = await importFreshEnvModule()
+  expect(getGlobalClaudeFile()).toBe(join(tempDir, '.claude.json'))
+})
+
+test('getGlobalClaudeFile: migrated user uses .openclaude.json when both files exist', async () => {
+  writeFileSync(join(tempDir, '.claude.json'), '{}')
+  writeFileSync(join(tempDir, '.openclaude.json'), '{}')
+  const { getGlobalClaudeFile } = await importFreshEnvModule()
+  expect(getGlobalClaudeFile()).toBe(join(tempDir, '.openclaude.json'))
+})