Add momentum strategy with QQQ-based TQQQ/SQQQ trading

Implements MomentumIndicator (samples QQQ direction) and
MomentumStrategy (buys TQQQ on up, SQQQ on down, exits at
+1% target or 1hr timeout). Wired into Bot via index.ts.
Also fixes vitest config to exclude dist/ from test discovery.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

vitest.config.ts

@@ -3,5 +3,6 @@ import { defineConfig } from 'vitest/config';
 export default defineConfig({
     test: {
         globals: true,
+        exclude: ['dist/**', 'node_modules/**'],
     },
 });