Add granular logging across all source files

Introduce logger infrastructure and add structured logging to every layer:
alpaca.ts (buy/sell/quote/clock), momentum-indicator.ts (evaluate flow),
momentum-strategy.ts (poll loop), index.ts (startup/cycle), and trading.ts
(market timing). Replace raw console.log calls with leveled logger. Update
all tests with appropriate console spies.

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

src/bot.ts

@@ -1,4 +1,5 @@
 import { Alpaca } from "./alpaca";
+import { logger } from "./logger";
 import { Strategy } from "./strategy";
 import { isMarketOpen, waitForNextOpen } from "./trading";
 
@@ -25,11 +26,14 @@ export class Bot {
     async runDay(): Promise<void> {
         const open = await isMarketOpen(this.alpaca);
         if (!open) {
-            console.log('waiting for open');
+            logger.info('waiting for open');
             await waitForNextOpen(this.alpaca);
         }
+        logger.info('market is open, running strategies');
         const account = await this.alpaca.getAccount();
+        logger.debug(`got account: ${JSON.stringify(account)}`);
         const totalCapital = parseFloat(account.cash);
+        logger.debug(`total capital: ${totalCapital}`);
 
         await Promise.all(
             this.allocations.map(async ({ strategy, capitalAllocation }) => {