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/checks/config.test.ts

@@ -0,0 +1,103 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as config from "./config"
+
+describe("config check", () => {
+  describe("validateConfig", () => {
+    it("returns valid: false for non-existent file", () => {
+      // #given non-existent file path
+      // #when validating
+      const result = config.validateConfig("/non/existent/path.json")
+
+      // #then should indicate invalid
+      expect(result.valid).toBe(false)
+      expect(result.errors.length).toBeGreaterThan(0)
+    })
+  })
+
+  describe("getConfigInfo", () => {
+    it("returns exists: false when no config found", () => {
+      // #given no config file exists
+      // #when getting config info
+      const info = config.getConfigInfo()
+
+      // #then should handle gracefully
+      expect(typeof info.exists).toBe("boolean")
+      expect(typeof info.valid).toBe("boolean")
+    })
+  })
+
+  describe("checkConfigValidity", () => {
+    let getInfoSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getInfoSpy?.mockRestore()
+    })
+
+    it("returns pass when no config exists (uses defaults)", async () => {
+      // #given no config file
+      getInfoSpy = spyOn(config, "getConfigInfo").mockReturnValue({
+        exists: false,
+        path: null,
+        format: null,
+        valid: true,
+        errors: [],
+      })
+
+      // #when checking validity
+      const result = await config.checkConfigValidity()
+
+      // #then should pass with default message
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("default")
+    })
+
+    it("returns pass when config is valid", async () => {
+      // #given valid config
+      getInfoSpy = spyOn(config, "getConfigInfo").mockReturnValue({
+        exists: true,
+        path: "/home/user/.config/opencode/oh-my-opencode.json",
+        format: "json",
+        valid: true,
+        errors: [],
+      })
+
+      // #when checking validity
+      const result = await config.checkConfigValidity()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("JSON")
+    })
+
+    it("returns fail when config has validation errors", async () => {
+      // #given invalid config
+      getInfoSpy = spyOn(config, "getConfigInfo").mockReturnValue({
+        exists: true,
+        path: "/home/user/.config/opencode/oh-my-opencode.json",
+        format: "json",
+        valid: false,
+        errors: ["agents.oracle: Invalid model format"],
+      })
+
+      // #when checking validity
+      const result = await config.checkConfigValidity()
+
+      // #then should fail with errors
+      expect(result.status).toBe("fail")
+      expect(result.details?.some((d) => d.includes("Error"))).toBe(true)
+    })
+  })
+
+  describe("getConfigCheckDefinition", () => {
+    it("returns valid check definition", () => {
+      // #given
+      // #when getting definition
+      const def = config.getConfigCheckDefinition()
+
+      // #then should have required properties
+      expect(def.id).toBe("config-validation")
+      expect(def.category).toBe("configuration")
+      expect(def.critical).toBe(false)
+    })
+  })
+})