refactor(launcher): split config parser and CLI builder

Decompose launcher/config.ts into focused domain parser and CLI normalization modules to reduce refactor risk while preserving command behavior. Align Jellyfin launcher config with session-based auth by dropping config token/userId dependency.

launcher/config/plugin-runtime-config.ts

@@ -0,0 +1,57 @@
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { log } from '../log.js';
+import type { LogLevel, PluginRuntimeConfig } from '../types.js';
+import { DEFAULT_SOCKET_PATH } from '../types.js';
+
+export function getPluginConfigCandidates(): string[] {
+  const xdgConfigHome = process.env.XDG_CONFIG_HOME || path.join(os.homedir(), '.config');
+  return Array.from(
+    new Set([
+      path.join(xdgConfigHome, 'mpv', 'script-opts', 'subminer.conf'),
+      path.join(os.homedir(), '.config', 'mpv', 'script-opts', 'subminer.conf'),
+    ]),
+  );
+}
+
+export function parsePluginRuntimeConfigContent(content: string): PluginRuntimeConfig {
+  const runtimeConfig: PluginRuntimeConfig = { socketPath: DEFAULT_SOCKET_PATH };
+  for (const line of content.split(/\r?\n/)) {
+    const trimmed = line.trim();
+    if (trimmed.length === 0 || trimmed.startsWith('#')) continue;
+    const socketMatch = trimmed.match(/^socket_path\s*=\s*(.+)$/i);
+    if (!socketMatch) continue;
+    const value = (socketMatch[1] || '').split('#', 1)[0]?.trim() || '';
+    if (value) runtimeConfig.socketPath = value;
+  }
+  return runtimeConfig;
+}
+
+export function readPluginRuntimeConfig(logLevel: LogLevel): PluginRuntimeConfig {
+  const candidates = getPluginConfigCandidates();
+  const defaults: PluginRuntimeConfig = { socketPath: DEFAULT_SOCKET_PATH };
+
+  for (const configPath of candidates) {
+    if (!fs.existsSync(configPath)) continue;
+    try {
+      const parsed = parsePluginRuntimeConfigContent(fs.readFileSync(configPath, 'utf8'));
+      log(
+        'debug',
+        logLevel,
+        `Using mpv plugin settings from ${configPath}: socket_path=${parsed.socketPath}`,
+      );
+      return parsed;
+    } catch {
+      log('warn', logLevel, `Failed to read ${configPath}; using launcher defaults`);
+      return defaults;
+    }
+  }
+
+  log(
+    'debug',
+    logLevel,
+    `No mpv subminer.conf found; using launcher defaults (socket_path=${defaults.socketPath})`,
+  );
+  return defaults;
+}