feat: add GET /api/admin/scraper/status endpoint

Implement a status endpoint that returns the current state of the
scraper system. The response includes mutex state (idle/running with
job ID), last run history from scraper_runs collection (status,
timing, unit/error counts), next scheduled run timestamp, and
cron schedule expression.

Protected by requireAuth + requireAdmin middleware. Returns 503
on database errors for graceful degradation. Includes 13 tests
covering auth, response structure, edge cases, and error handling.

routes/admin.js

@@ -1150,9 +1150,13 @@ const crypto = require('crypto');
 const {
   isScraperRunning,
   acquireLock,
-  releaseLock
+  releaseLock,
+  getCurrentJobId,
+  getScheduleExpression,
+  getNextScheduledRun
 } = require('../jobs/scraperJob');
 const { runScrape } = require('../services/scraperService');
+const scraperConfig = require('../config/scraper');
 
 /**
  * POST /api/admin/scraper/run
@@ -1206,5 +1210,45 @@ router.post('/scraper/run', async (req, res) => {
   }
 });
 
+/**
+ * GET /api/admin/scraper/status
+ * Get current scraper status including running state, last run details,
+ * next scheduled run, and schedule expression.
+ */
+router.get('/scraper/status', async (req, res) => {
+  try {
+    const db = req.app.locals.db;
+
+    // Get last run from history
+    const lastRunDoc = await db.collection(scraperConfig.COLLECTIONS.SCRAPER_RUNS)
+      .findOne({}, { sort: { startedAt: -1 } });
+
+    const lastRun = lastRunDoc ? {
+      jobId: lastRunDoc.jobId,
+      timestamp: lastRunDoc.startedAt,
+      status: lastRunDoc.status,
+      duration: lastRunDoc.duration,
+      trigger: lastRunDoc.trigger,
+      unitsProcessed: lastRunDoc.unitsProcessed,
+      pricesInserted: lastRunDoc.pricesInserted,
+      errors: lastRunDoc.errors?.length > 0 ? lastRunDoc.errors : null
+    } : null;
+
+    res.json({
+      data: {
+        currentStatus: isScraperRunning() ? 'running' : 'idle',
+        runningJobId: isScraperRunning() ? getCurrentJobId() : null,
+        lastRun,
+        nextScheduledRun: getNextScheduledRun(),
+        schedule: getScheduleExpression()
+      }
+    });
+
+  } catch (error) {
+    console.error('Error fetching scraper status:', error);
+    res.status(503).json({ error: 'Service temporarily unavailable' });
+  }
+});
+
 module.exports = router;
 module.exports.clearStatsCache = clearStatsCache;