refactor(doctor): redesign with 3-tier output and consolidated checks

Consolidate 16 separate checks into 5 (system, config, providers, tools, models).
Add 3-tier formatting: default (problems-only), --status (dashboard), --verbose (deep diagnostics).
Read actual loaded plugin version from opencode cache directory.
Check environment variables for provider authentication.

src/cli/doctor/checks/system-loaded-version.ts

@@ -0,0 +1,79 @@
+import { existsSync, readFileSync } from "node:fs"
+import { homedir } from "node:os"
+import { join } from "node:path"
+
+import { getLatestVersion } from "../../../hooks/auto-update-checker/checker"
+import { extractChannel } from "../../../hooks/auto-update-checker"
+import { PACKAGE_NAME } from "../constants"
+import { getOpenCodeCacheDir, parseJsonc } from "../../../shared"
+
+interface PackageJsonShape {
+  version?: string
+  dependencies?: Record<string, string>
+}
+
+export interface LoadedVersionInfo {
+  cacheDir: string
+  cachePackagePath: string
+  installedPackagePath: string
+  expectedVersion: string | null
+  loadedVersion: string | null
+}
+
+function getPlatformDefaultCacheDir(platform: NodeJS.Platform = process.platform): string {
+  if (platform === "darwin") return join(homedir(), "Library", "Caches")
+  if (platform === "win32") return process.env.LOCALAPPDATA ?? join(homedir(), "AppData", "Local")
+  return join(homedir(), ".cache")
+}
+
+function resolveOpenCodeCacheDir(): string {
+  const xdgCacheHome = process.env.XDG_CACHE_HOME
+  if (xdgCacheHome) return join(xdgCacheHome, "opencode")
+
+  const fromShared = getOpenCodeCacheDir()
+  const platformDefault = join(getPlatformDefaultCacheDir(), "opencode")
+  if (existsSync(fromShared) || !existsSync(platformDefault)) return fromShared
+  return platformDefault
+}
+
+function readPackageJson(filePath: string): PackageJsonShape | null {
+  if (!existsSync(filePath)) return null
+
+  try {
+    const content = readFileSync(filePath, "utf-8")
+    return parseJsonc<PackageJsonShape>(content)
+  } catch {
+    return null
+  }
+}
+
+function normalizeVersion(value: string | undefined): string | null {
+  if (!value) return null
+  const match = value.match(/\d+\.\d+\.\d+(?:-[0-9A-Za-z.-]+)?/)
+  return match?.[0] ?? null
+}
+
+export function getLoadedPluginVersion(): LoadedVersionInfo {
+  const cacheDir = resolveOpenCodeCacheDir()
+  const cachePackagePath = join(cacheDir, "package.json")
+  const installedPackagePath = join(cacheDir, "node_modules", PACKAGE_NAME, "package.json")
+
+  const cachePackage = readPackageJson(cachePackagePath)
+  const installedPackage = readPackageJson(installedPackagePath)
+
+  const expectedVersion = normalizeVersion(cachePackage?.dependencies?.[PACKAGE_NAME])
+  const loadedVersion = normalizeVersion(installedPackage?.version)
+
+  return {
+    cacheDir,
+    cachePackagePath,
+    installedPackagePath,
+    expectedVersion,
+    loadedVersion,
+  }
+}
+
+export async function getLatestPluginVersion(currentVersion: string | null): Promise<string | null> {
+  const channel = extractChannel(currentVersion)
+  return getLatestVersion(channel)
+}