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/tools-gh.ts

@@ -0,0 +1,105 @@
+export interface GhCliInfo {
+  installed: boolean
+  version: string | null
+  path: string | null
+  authenticated: boolean
+  username: string | null
+  scopes: string[]
+  error: string | null
+}
+
+async function checkBinaryExists(binary: string): Promise<{ exists: boolean; path: string | null }> {
+  try {
+    const binaryPath = Bun.which(binary)
+    return { exists: Boolean(binaryPath), path: binaryPath ?? null }
+  } catch {
+    return { exists: false, path: null }
+  }
+}
+
+async function getGhVersion(): Promise<string | null> {
+  try {
+    const processResult = Bun.spawn(["gh", "--version"], { stdout: "pipe", stderr: "pipe" })
+    const output = await new Response(processResult.stdout).text()
+    await processResult.exited
+    if (processResult.exitCode !== 0) return null
+
+    const matchedVersion = output.match(/gh version (\S+)/)
+    return matchedVersion?.[1] ?? output.trim().split("\n")[0] ?? null
+  } catch {
+    return null
+  }
+}
+
+async function getGhAuthStatus(): Promise<{
+  authenticated: boolean
+  username: string | null
+  scopes: string[]
+  error: string | null
+}> {
+  try {
+    const processResult = Bun.spawn(["gh", "auth", "status"], {
+      stdout: "pipe",
+      stderr: "pipe",
+      env: { ...process.env, GH_NO_UPDATE_NOTIFIER: "1" },
+    })
+
+    const stdout = await new Response(processResult.stdout).text()
+    const stderr = await new Response(processResult.stderr).text()
+    await processResult.exited
+
+    const output = stderr || stdout
+    if (processResult.exitCode === 0) {
+      const usernameMatch = output.match(/Logged in to github\.com account (\S+)/)
+      const scopesMatch = output.match(/Token scopes?:\s*(.+)/i)
+
+      return {
+        authenticated: true,
+        username: usernameMatch?.[1]?.replace(/[()]/g, "") ?? null,
+        scopes: scopesMatch?.[1]?.split(/,\s*/).map((scope) => scope.trim()).filter(Boolean) ?? [],
+        error: null,
+      }
+    }
+
+    const errorMatch = output.match(/error[:\s]+(.+)/i)
+    return {
+      authenticated: false,
+      username: null,
+      scopes: [],
+      error: errorMatch?.[1]?.trim() ?? "Not authenticated",
+    }
+  } catch (error) {
+    return {
+      authenticated: false,
+      username: null,
+      scopes: [],
+      error: error instanceof Error ? error.message : "Failed to check auth status",
+    }
+  }
+}
+
+export async function getGhCliInfo(): Promise<GhCliInfo> {
+  const binaryStatus = await checkBinaryExists("gh")
+  if (!binaryStatus.exists) {
+    return {
+      installed: false,
+      version: null,
+      path: null,
+      authenticated: false,
+      username: null,
+      scopes: [],
+      error: null,
+    }
+  }
+
+  const [version, authStatus] = await Promise.all([getGhVersion(), getGhAuthStatus()])
+  return {
+    installed: true,
+    version,
+    path: binaryStatus.path,
+    authenticated: authStatus.authenticated,
+    username: authStatus.username,
+    scopes: authStatus.scopes,
+    error: authStatus.error,
+  }
+}