Refactor dashboard JS to ES modules; fix collector strategy loading and add auto-backfill

- Split inline JS into separate ES module files (indicators/, strategies/, ui/, utils/)
- Fix brain.py strategy registry to use MAStrategy directly instead of missing modules
- Add auto-backfill for detected data gaps in collector monitoring loop
- Fix chart resize on sidebar toggle
- Fix chart scrollToTime -> setVisibleLogicalRange

src/api/dashboard/static/js/indicators/stoch.js

@@ -0,0 +1,44 @@
+import { BaseIndicator } from './base.js';
+
+export class StochasticIndicator extends BaseIndicator {
+    calculate(candles) {
+        const kPeriod = this.params.kPeriod || 14;
+        const dPeriod = this.params.dPeriod || 3;
+        const results = new Array(candles.length).fill(null);
+        
+        const kValues = new Array(candles.length).fill(null);
+        
+        for (let i = kPeriod - 1; i < candles.length; i++) {
+            let lowest = Infinity;
+            let highest = -Infinity;
+            for (let j = 0; j < kPeriod; j++) {
+                lowest = Math.min(lowest, candles[i-j].low);
+                highest = Math.max(highest, candles[i-j].high);
+            }
+            const diff = highest - lowest;
+            kValues[i] = diff === 0 ? 50 : ((candles[i].close - lowest) / diff) * 100;
+        }
+        
+        for (let i = kPeriod + dPeriod - 2; i < candles.length; i++) {
+            let sum = 0;
+            for (let j = 0; j < dPeriod; j++) sum += kValues[i-j];
+            results[i] = { k: kValues[i], d: sum / dPeriod };
+        }
+        
+        return results;
+    }
+    
+    getMetadata() {
+        return {
+            name: 'Stochastic',
+            inputs: [
+                { name: 'kPeriod', label: 'K Period', type: 'number', default: 14 },
+                { name: 'dPeriod', label: 'D Period', type: 'number', default: 3 }
+            ],
+            plots: [
+                { id: 'k', color: '#3f51b5', title: '%K' },
+                { id: 'd', color: '#ff9800', title: '%D' }
+            ]
+        };
+    }
+}