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-binary.ts

@@ -0,0 +1,144 @@
+import { existsSync } from "node:fs"
+import { homedir } from "node:os"
+import { join } from "node:path"
+
+import { OPENCODE_BINARIES } from "../constants"
+
+const WINDOWS_EXECUTABLE_EXTS = [".exe", ".cmd", ".bat", ".ps1"]
+
+export interface OpenCodeBinaryInfo {
+  binary: string
+  path: string
+}
+
+export function getDesktopAppPaths(platform: NodeJS.Platform): string[] {
+  const home = homedir()
+
+  switch (platform) {
+    case "darwin":
+      return [
+        "/Applications/OpenCode.app/Contents/MacOS/OpenCode",
+        join(home, "Applications", "OpenCode.app", "Contents", "MacOS", "OpenCode"),
+      ]
+    case "win32": {
+      const programFiles = process.env.ProgramFiles
+      const localAppData = process.env.LOCALAPPDATA
+      const paths: string[] = []
+
+      if (programFiles) {
+        paths.push(join(programFiles, "OpenCode", "OpenCode.exe"))
+      }
+      if (localAppData) {
+        paths.push(join(localAppData, "OpenCode", "OpenCode.exe"))
+      }
+
+      return paths
+    }
+    case "linux":
+      return [
+        "/usr/bin/opencode",
+        "/usr/lib/opencode/opencode",
+        join(home, "Applications", "opencode-desktop-linux-x86_64.AppImage"),
+        join(home, "Applications", "opencode-desktop-linux-aarch64.AppImage"),
+      ]
+    default:
+      return []
+  }
+}
+
+export function getBinaryLookupCommand(platform: NodeJS.Platform): "which" | "where" {
+  return platform === "win32" ? "where" : "which"
+}
+
+export function parseBinaryPaths(output: string): string[] {
+  return output
+    .split(/\r?\n/)
+    .map((line) => line.trim())
+    .filter((line) => line.length > 0)
+}
+
+export function selectBinaryPath(paths: string[], platform: NodeJS.Platform): string | null {
+  if (paths.length === 0) return null
+  if (platform !== "win32") return paths[0] ?? null
+
+  const normalizedPaths = paths.map((path) => path.toLowerCase())
+  for (const extension of WINDOWS_EXECUTABLE_EXTS) {
+    const pathIndex = normalizedPaths.findIndex((path) => path.endsWith(extension))
+    if (pathIndex !== -1) {
+      return paths[pathIndex] ?? null
+    }
+  }
+
+  return paths[0] ?? null
+}
+
+export function buildVersionCommand(binaryPath: string, platform: NodeJS.Platform): string[] {
+  if (platform === "win32" && binaryPath.toLowerCase().endsWith(".ps1")) {
+    return ["powershell", "-NoProfile", "-ExecutionPolicy", "Bypass", "-File", binaryPath, "--version"]
+  }
+
+  return [binaryPath, "--version"]
+}
+
+export function findDesktopBinary(
+  platform: NodeJS.Platform = process.platform,
+  checkExists: (path: string) => boolean = existsSync
+): OpenCodeBinaryInfo | null {
+  for (const desktopPath of getDesktopAppPaths(platform)) {
+    if (checkExists(desktopPath)) {
+      return { binary: "opencode", path: desktopPath }
+    }
+  }
+
+  return null
+}
+
+export async function findOpenCodeBinary(): Promise<OpenCodeBinaryInfo | null> {
+  for (const binary of OPENCODE_BINARIES) {
+    const path = Bun.which(binary)
+    if (path) {
+      return { binary, path }
+    }
+  }
+
+  return findDesktopBinary()
+}
+
+export async function getOpenCodeVersion(
+  binaryPath: string,
+  platform: NodeJS.Platform = process.platform
+): Promise<string | null> {
+  try {
+    const command = buildVersionCommand(binaryPath, platform)
+    const processResult = Bun.spawn(command, { stdout: "pipe", stderr: "pipe" })
+    const output = await new Response(processResult.stdout).text()
+    await processResult.exited
+
+    if (processResult.exitCode !== 0) return null
+    return output.trim() || null
+  } catch {
+    return null
+  }
+}
+
+export function compareVersions(current: string, minimum: string): boolean {
+  const parseVersion = (version: string): number[] =>
+    version
+      .replace(/^v/, "")
+      .split("-")[0]
+      .split(".")
+      .map((part) => Number.parseInt(part, 10) || 0)
+
+  const currentParts = parseVersion(current)
+  const minimumParts = parseVersion(minimum)
+  const length = Math.max(currentParts.length, minimumParts.length)
+
+  for (let index = 0; index < length; index++) {
+    const currentPart = currentParts[index] ?? 0
+    const minimumPart = minimumParts[index] ?? 0
+    if (currentPart > minimumPart) return true
+    if (currentPart < minimumPart) return false
+  }
+
+  return true
+}