fix(config): store config.json under the persisted data dir (#86)

CONFIG_PATH resolved to ROOT_DIR/config.json (/app/config.json in Docker), but only
DATA_DIR (/app/data) is the mounted volume — every other artifact (DB, cookies, logs,
avatars) already lives under DATA_DIR. So on first run the default config was written
into the ephemeral image layer (never appearing in the volume), and a manually-placed
data/config.json was ignored because the bot read/wrote the root path.

- Move CONFIG_PATH to DATA_DIR/config.json so it lands in the volume and manual edits
  take effect.
- Add migrateLegacyConfig(): one-time move of an existing root-level config.json into
  the data dir, so existing local installs keep their settings (no silent reset).
- Tests for first-run persistence + the three migration cases.
- README directory tree updated to data/config.json.

Fixes #86

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -383,11 +383,11 @@ teamspeak-music-bot/
 │   └── docker/                 # Docker 部署文件
 │       ├── Dockerfile
 │       └── docker-compose.yml
-├── data/                       # 运行时数据（自动创建，不上传）
-│   ├── tsmusicbot.db           # SQLite 数据库
-│   ├── cookies/                # 登录 Cookie
-│   └── logs/                   # 日志文件
-└── config.json                 # 配置文件（首次运行自动生成，不上传）
+└── data/                       # 运行时数据（自动创建，不上传）
+    ├── config.json             # 配置文件（首次运行自动生成，可手动编辑）
+    ├── tsmusicbot.db           # SQLite 数据库
+    ├── cookies/                # 登录 Cookie
+    └── logs/                   # 日志文件
 ```
 
 ## 技术栈

src/data/config.test.ts

@@ -1,8 +1,8 @@
 import { describe, it, expect, afterEach } from "vitest";
 import { join } from "node:path";
-import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { mkdtempSync, rmSync, writeFileSync, existsSync, readFileSync } from "node:fs";
 import { tmpdir } from "node:os";
-import { getDefaultConfig, loadConfig, saveConfig } from "./config.js";
+import { getDefaultConfig, loadConfig, saveConfig, migrateLegacyConfig } from "./config.js";
 
 describe("config", () => {
   const dirs: string[] = [];
@@ -51,4 +51,57 @@ describe("config", () => {
     expect(loaded.commandPrefix).toBe("!");
     expect(loaded.autoPauseOnEmpty).toBe(true);
   });
+
+  // --- #86: config.json must live under (and be created in) the persisted data dir ---
+
+  it("first run writes config.json into the data dir and reads it back", () => {
+    const root = makeTmpDir();
+    const dataDir = join(root, "data");
+    const configPath = join(dataDir, "config.json"); // mirrors index.ts CONFIG_PATH
+
+    // Boot sequence: load (missing -> defaults) then save.
+    const config = loadConfig(configPath);
+    saveConfig(configPath, config);
+
+    expect(existsSync(configPath)).toBe(true);
+    // A subsequent hand-edited file under the SAME persisted path is honored.
+    writeFileSync(configPath, JSON.stringify({ webPort: 9999 }), "utf-8");
+    expect(loadConfig(configPath).webPort).toBe(9999);
+  });
+
+  it("migrates a legacy root config into the data dir, preserving values", () => {
+    const root = makeTmpDir();
+    const legacyPath = join(root, "config.json");
+    const newPath = join(root, "data", "config.json");
+    writeFileSync(legacyPath, JSON.stringify({ webPort: 4242, publicUrl: "http://x" }), "utf-8");
+
+    const migrated = migrateLegacyConfig(legacyPath, newPath);
+
+    expect(migrated).toBe(true);
+    expect(existsSync(newPath)).toBe(true);
+    expect(existsSync(legacyPath)).toBe(false); // legacy moved, not duplicated
+    const loaded = loadConfig(newPath);
+    expect(loaded.webPort).toBe(4242);
+    expect(loaded.publicUrl).toBe("http://x");
+  });
+
+  it("does NOT overwrite an existing data-dir config during migration", () => {
+    const root = makeTmpDir();
+    const legacyPath = join(root, "config.json");
+    const newPath = join(root, "data", "config.json");
+    writeFileSync(legacyPath, JSON.stringify({ webPort: 1111 }), "utf-8");
+    saveConfig(newPath, { ...getDefaultConfig(), webPort: 2222 });
+
+    const migrated = migrateLegacyConfig(legacyPath, newPath);
+
+    expect(migrated).toBe(false); // new location wins, untouched
+    expect(loadConfig(newPath).webPort).toBe(2222);
+    expect(existsSync(legacyPath)).toBe(true); // legacy left intact when not migrated
+  });
+
+  it("migration is a no-op when there is no legacy config", () => {
+    const root = makeTmpDir();
+    const migrated = migrateLegacyConfig(join(root, "config.json"), join(root, "data", "config.json"));
+    expect(migrated).toBe(false);
+  });
 });

src/data/config.ts

@@ -1,4 +1,4 @@
-import { readFileSync, writeFileSync, mkdirSync } from "node:fs";
+import { readFileSync, writeFileSync, mkdirSync, existsSync, copyFileSync, rmSync } from "node:fs";
 import { dirname } from "node:path";
 
 export interface BotConfig {
@@ -58,3 +58,35 @@ export function saveConfig(path: string, config: BotConfig): void {
   mkdirSync(dirname(path), { recursive: true });
   writeFileSync(path, JSON.stringify(config, null, 2), "utf-8");
 }
+
+/**
+ * One-time migration for the config location fix (#86).
+ *
+ * Older versions wrote config.json to the app/repo ROOT, which is NOT inside the
+ * persisted data directory (the Docker volume is mounted at data/). That meant the
+ * file never landed in the volume on first run and a manually-placed data/config.json
+ * was ignored. config.json now lives under the data dir alongside the DB/cookies/logs.
+ *
+ * If a legacy root-level config exists and the new data-dir config does not yet exist,
+ * move it so existing local installs keep their customized settings. Best-effort:
+ * any failure is swallowed and loadConfig falls back to defaults.
+ *
+ * @returns true if a legacy config was migrated, false otherwise.
+ */
+export function migrateLegacyConfig(legacyPath: string, newPath: string): boolean {
+  try {
+    if (legacyPath === newPath) return false;
+    if (existsSync(newPath)) return false; // new location already populated — leave it
+    if (!existsSync(legacyPath)) return false; // nothing to migrate
+    mkdirSync(dirname(newPath), { recursive: true });
+    copyFileSync(legacyPath, newPath); // copy first (works across filesystems)
+    try {
+      rmSync(legacyPath);
+    } catch {
+      /* leave the legacy file if it can't be removed; the new one wins */
+    }
+    return true;
+  } catch {
+    return false;
+  }
+}

src/index.ts

@@ -1,6 +1,6 @@
 import path from "node:path";
 import { fileURLToPath } from "node:url";
-import { loadConfig, saveConfig } from "./data/config.js";
+import { loadConfig, saveConfig, migrateLegacyConfig } from "./data/config.js";
 import { createDatabase } from "./data/database.js";
 import { createLogger } from "./logger.js";
 import { createApiServerManager } from "./music/api-server.js";
@@ -16,7 +16,11 @@ import { createWebServer } from "./web/server.js";
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const ROOT_DIR = path.resolve(__dirname, "..");
 const DATA_DIR = path.join(ROOT_DIR, "data");
-const CONFIG_PATH = path.join(ROOT_DIR, "config.json");
+// config.json lives under the persisted data dir (the Docker volume) alongside the
+// DB/cookies/logs, so it survives container restarts and manual edits take effect
+// (#86). LEGACY_CONFIG_PATH is the old root-level location we migrate from once.
+const CONFIG_PATH = path.join(DATA_DIR, "config.json");
+const LEGACY_CONFIG_PATH = path.join(ROOT_DIR, "config.json");
 const DB_PATH = path.join(DATA_DIR, "tsmusicbot.db");
 const LOG_DIR = path.join(DATA_DIR, "logs");
 const COOKIE_DIR = path.join(DATA_DIR, "cookies");
@@ -24,6 +28,9 @@ const AVATAR_DIR = path.join(DATA_DIR, "avatars");
 const STATIC_DIR = path.join(ROOT_DIR, "web", "dist");
 
 async function main() {
+  // Migrate a pre-#86 root-level config.json into the data dir so existing
+  // installs keep their settings; no-op if already migrated or none exists.
+  migrateLegacyConfig(LEGACY_CONFIG_PATH, CONFIG_PATH);
   const config = loadConfig(CONFIG_PATH);
   saveConfig(CONFIG_PATH, config);