fix: respect OPENCODE_CONFIG_DIR environment variable across all config paths

Multiple files were hardcoding ~/.config/opencode paths instead of using
getOpenCodeConfigDir() which respects the OPENCODE_CONFIG_DIR env var.

This broke profile isolation features like OCX ghost mode, where users
set OPENCODE_CONFIG_DIR to a custom path but oh-my-opencode.json and
other configs weren't being read from that location.

Changes:
- plugin-config.ts: Use getOpenCodeConfigDir() directly
- cli/doctor/checks: Use getOpenCodeConfigDir() for auth and config checks
- tools/lsp/config.ts: Use getOpenCodeConfigDir() for LSP config paths
- command loaders: Use getOpenCodeConfigDir() for global command dirs
- hooks: Use getOpenCodeConfigDir() for hook config paths
- config-path.ts: Mark getUserConfigDir() as deprecated
- tests: Ensure OPENCODE_CONFIG_DIR is properly isolated in tests

src/hooks/claude-code-hooks/config-loader.ts

@@ -1,8 +1,8 @@
 import { existsSync } from "fs"
-import { homedir } from "os"
 import { join } from "path"
 import type { ClaudeHookEvent } from "./types"
 import { log } from "../../shared/logger"
+import { getOpenCodeConfigDir } from "../../shared"
 
 export interface DisabledHooksConfig {
   Stop?: string[]
@@ -16,7 +16,7 @@ export interface PluginExtendedConfig {
   disabledHooks?: DisabledHooksConfig
 }
 
-const USER_CONFIG_PATH = join(homedir(), ".config", "opencode", "opencode-cc-plugin.json")
+const USER_CONFIG_PATH = join(getOpenCodeConfigDir({ binary: "opencode" }), "opencode-cc-plugin.json")
 
 function getProjectConfigPath(): string {
   return join(process.cwd(), ".opencode", "opencode-cc-plugin.json")