fix: add config validation and retry logic for failed jobs

- Add loadConfig() helper with clear errors for missing/malformed JSON
- Replace raw JSON.parse(readFileSync(...)) in both entry points
- Track retry_count on jobs; re-queue as 'new' up to max_retries (default 2)
- Add max_retries and DEFAULT_MAX_RETRIES constant

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

lib/constants.mjs

@@ -53,3 +53,4 @@ export const NOTIFY_RATE_LIMIT_MS = 1500;
 
 // --- Queue ---
 export const DEFAULT_REVIEW_WINDOW_MINUTES = 30;
+export const DEFAULT_MAX_RETRIES = 2;

lib/queue.mjs

@@ -3,13 +3,34 @@
  * Handles jobs_queue.json read/write/update
  */
 import { readFileSync, writeFileSync, existsSync, mkdirSync } from 'fs';
-import { dirname } from 'path';
+import { dirname, resolve } from 'path';
 import { fileURLToPath } from 'url';
 
 const __dir = dirname(fileURLToPath(import.meta.url));
 const QUEUE_PATH = `${__dir}/../data/jobs_queue.json`;
 const LOG_PATH = `${__dir}/../data/applications_log.json`;
 
+/**
+ * Load and validate a JSON config file. Throws with a clear message on failure.
+ */
+export function loadConfig(filePath) {
+  const resolved = resolve(filePath);
+  if (!existsSync(resolved)) {
+    throw new Error(`Config file not found: ${resolved}\nCopy the matching .example.json and fill in your values.`);
+  }
+  let raw;
+  try {
+    raw = readFileSync(resolved, 'utf8');
+  } catch (e) {
+    throw new Error(`Cannot read config file ${resolved}: ${e.message}`);
+  }
+  try {
+    return JSON.parse(raw);
+  } catch (e) {
+    throw new Error(`Invalid JSON in ${resolved}: ${e.message}`);
+  }
+}
+
 function ensureDir(path) {
   const dir = dirname(path);
   if (!existsSync(dir)) mkdirSync(dir, { recursive: true });