feat(cli): add doctor command for installation health checks (#334)

Implements a comprehensive 'doctor' command that diagnoses oh-my-opencode
installation health with a beautiful TUI output.

Checks performed:
- OpenCode installation (version, path, binary)
- Plugin registration in opencode.json
- Configuration file validity (oh-my-opencode.json)
- Auth providers (Anthropic, OpenAI, Google)
- Dependencies (ast-grep CLI/NAPI, comment-checker)
- LSP servers availability
- MCP servers (builtin and user)
- Version status and updates

Features:
- Beautiful TUI with symbols and colors
- --verbose flag for detailed output
- --json flag for machine-readable output
- --category flag for running specific checks
- Exit code 1 on failures for CI integration

Closes #333

Co-authored-by: sisyphus-dev-ai <sisyphus-dev-ai@users.noreply.github.com>

src/cli/doctor/runner.ts

@@ -0,0 +1,132 @@
+import type {
+  DoctorOptions,
+  DoctorResult,
+  CheckDefinition,
+  CheckResult,
+  DoctorSummary,
+  CheckCategory,
+} from "./types"
+import { getAllCheckDefinitions } from "./checks"
+import { EXIT_CODES, CATEGORY_NAMES } from "./constants"
+import {
+  formatHeader,
+  formatCategoryHeader,
+  formatCheckResult,
+  formatSummary,
+  formatFooter,
+  formatJsonOutput,
+} from "./formatter"
+
+export async function runCheck(check: CheckDefinition): Promise<CheckResult> {
+  const start = performance.now()
+  try {
+    const result = await check.check()
+    result.duration = Math.round(performance.now() - start)
+    return result
+  } catch (err) {
+    return {
+      name: check.name,
+      status: "fail",
+      message: err instanceof Error ? err.message : "Unknown error",
+      duration: Math.round(performance.now() - start),
+    }
+  }
+}
+
+export function calculateSummary(results: CheckResult[], duration: number): DoctorSummary {
+  return {
+    total: results.length,
+    passed: results.filter((r) => r.status === "pass").length,
+    failed: results.filter((r) => r.status === "fail").length,
+    warnings: results.filter((r) => r.status === "warn").length,
+    skipped: results.filter((r) => r.status === "skip").length,
+    duration: Math.round(duration),
+  }
+}
+
+export function determineExitCode(results: CheckResult[]): number {
+  const hasFailures = results.some((r) => r.status === "fail")
+  return hasFailures ? EXIT_CODES.FAILURE : EXIT_CODES.SUCCESS
+}
+
+export function filterChecksByCategory(
+  checks: CheckDefinition[],
+  category?: CheckCategory
+): CheckDefinition[] {
+  if (!category) return checks
+  return checks.filter((c) => c.category === category)
+}
+
+export function groupChecksByCategory(
+  checks: CheckDefinition[]
+): Map<CheckCategory, CheckDefinition[]> {
+  const groups = new Map<CheckCategory, CheckDefinition[]>()
+
+  for (const check of checks) {
+    const existing = groups.get(check.category) ?? []
+    existing.push(check)
+    groups.set(check.category, existing)
+  }
+
+  return groups
+}
+
+const CATEGORY_ORDER: CheckCategory[] = [
+  "installation",
+  "configuration",
+  "authentication",
+  "dependencies",
+  "tools",
+  "updates",
+]
+
+export async function runDoctor(options: DoctorOptions): Promise<DoctorResult> {
+  const start = performance.now()
+  const allChecks = getAllCheckDefinitions()
+  const filteredChecks = filterChecksByCategory(allChecks, options.category)
+  const groupedChecks = groupChecksByCategory(filteredChecks)
+
+  const results: CheckResult[] = []
+
+  if (!options.json) {
+    console.log(formatHeader())
+  }
+
+  for (const category of CATEGORY_ORDER) {
+    const checks = groupedChecks.get(category)
+    if (!checks || checks.length === 0) continue
+
+    if (!options.json) {
+      console.log(formatCategoryHeader(category))
+    }
+
+    for (const check of checks) {
+      const result = await runCheck(check)
+      results.push(result)
+
+      if (!options.json) {
+        console.log(formatCheckResult(result, options.verbose ?? false))
+      }
+    }
+  }
+
+  const duration = performance.now() - start
+  const summary = calculateSummary(results, duration)
+  const exitCode = determineExitCode(results)
+
+  const doctorResult: DoctorResult = {
+    results,
+    summary,
+    exitCode,
+  }
+
+  if (options.json) {
+    console.log(formatJsonOutput(doctorResult))
+  } else {
+    console.log("")
+    console.log(formatSummary(summary))
+    console.log(formatFooter(summary))
+  }
+
+  return doctorResult
+}