chore: clean up dead code, use shared loadConfig, cache queue I/O

- Remove unused readFileSync import from job_applier.mjs
- Remove unused makeJobId (dead code, nothing imports it)
- setup.mjs: use shared loadConfig instead of inline cfg()
- queue.mjs: add in-memory cache for queue and log to avoid
  redundant disk reads during a single run

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/queue.mjs

@@ -1,6 +1,7 @@
 /**
  * queue.mjs — Job queue management
  * Handles jobs_queue.json read/write/update
+ * Uses in-memory cache to avoid redundant disk I/O within a run.
  */
 import { readFileSync, writeFileSync, existsSync, mkdirSync } from 'fs';
 import { dirname, resolve } from 'path';
@@ -36,25 +37,39 @@ function ensureDir(path) {
   if (!existsSync(dir)) mkdirSync(dir, { recursive: true });
 }
 
+// --- In-memory caches (populated on first read, invalidated on write) ---
+let _queueCache = null;
+let _logCache = null;
+
 export function loadQueue() {
+  if (_queueCache) return _queueCache;
   ensureDir(QUEUE_PATH);
-  return existsSync(QUEUE_PATH) ? JSON.parse(readFileSync(QUEUE_PATH, 'utf8')) : [];
+  _queueCache = existsSync(QUEUE_PATH) ? JSON.parse(readFileSync(QUEUE_PATH, 'utf8')) : [];
+  return _queueCache;
 }
 
 export function saveQueue(jobs) {
   ensureDir(QUEUE_PATH);
   writeFileSync(QUEUE_PATH, JSON.stringify(jobs, null, 2));
+  _queueCache = jobs;
 }
 
-export function loadLog() {
+function loadLog() {
+  if (_logCache) return _logCache;
   ensureDir(LOG_PATH);
-  return existsSync(LOG_PATH) ? JSON.parse(readFileSync(LOG_PATH, 'utf8')) : [];
+  _logCache = existsSync(LOG_PATH) ? JSON.parse(readFileSync(LOG_PATH, 'utf8')) : [];
+  return _logCache;
+}
+
+function saveLog(log) {
+  writeFileSync(LOG_PATH, JSON.stringify(log, null, 2));
+  _logCache = log;
 }
 
 export function appendLog(entry) {
   const log = loadLog();
   log.push({ ...entry, logged_at: new Date().toISOString() });
-  writeFileSync(LOG_PATH, JSON.stringify(log, null, 2));
+  saveLog(log);
 }
 
 export function getJobsByStatus(status) {
@@ -100,9 +115,3 @@ export function addJobs(newJobs) {
   saveQueue(queue);
   return added;
 }
-
-export function makeJobId(platform, url) {
-  const match = url.match(/\/(\d{8,})/);
-  const id = match ? match[1] : Math.random().toString(36).slice(2, 10);
-  return `${platform}_${id}`;
-}