Add earnings calendar feature with command and scheduled delivery

Implement comprehensive earnings calendar functionality that displays upcoming earnings for major companies (market cap > $10B). Feature includes both manual command access and automated weekly delivery.

Key additions:
- Finnhub API integration for earnings calendar data with market cap filtering
- Discord embed formatting grouped by day with EPS/revenue estimates
- !earnings command for manual queries (current or next week)
- Weekly scheduled task (Sunday 6PM ET) for automatic delivery
- Configuration options for market cap threshold and schedule timing

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

stock_api/finnhub_api.py

@@ -90,3 +90,83 @@ class FinnhubAPI(StockAPIBase):
         except Exception as e:
             logger.error(f"Finnhub API unavailable: {e}")
             return False
+
+    def get_earnings_calendar(self, from_date: str, to_date: str, min_market_cap: float = 10_000_000_000) -> Optional[list]:
+        """
+        Retrieve earnings calendar for date range, filtered by market cap.
+
+        Args:
+            from_date: Start date (YYYY-MM-DD)
+            to_date: End date (YYYY-MM-DD)
+            min_market_cap: Minimum market cap threshold in dollars (default 10B)
+
+        Returns:
+            List of enriched earnings dictionaries, or None if unavailable
+        """
+        try:
+            # Fetch earnings calendar from Finnhub
+            earnings_data = self.client.earnings_calendar(_from=from_date, to=to_date, symbol='', international=False)
+
+            if not earnings_data or 'earningsCalendar' not in earnings_data:
+                logger.warning(f"No earnings data available for {from_date} to {to_date}")
+                return []
+
+            earnings_list = earnings_data['earningsCalendar']
+
+            if not earnings_list:
+                logger.info(f"No earnings found for {from_date} to {to_date}")
+                return []
+
+            # Enrich each earning with company profile data and filter by market cap
+            enriched_earnings = []
+
+            for earning in earnings_list:
+                symbol = earning.get('symbol')
+                if not symbol:
+                    continue
+
+                try:
+                    # Fetch company profile for market cap and name
+                    profile = self.client.company_profile2(symbol=symbol)
+
+                    if not profile:
+                        logger.debug(f"No profile data for {symbol}")
+                        continue
+
+                    # Market cap in Finnhub is in millions, convert to dollars
+                    market_cap = profile.get('marketCapitalization', 0) * 1_000_000
+
+                    # Filter by minimum market cap
+                    if market_cap < min_market_cap:
+                        continue
+
+                    # Enrich earnings data
+                    enriched_earning = {
+                        'symbol': symbol,
+                        'company_name': profile.get('name', symbol),
+                        'market_cap': market_cap,
+                        'date': earning.get('date'),
+                        'eps_estimate': earning.get('epsEstimate'),
+                        'eps_actual': earning.get('epsActual'),
+                        'revenue_estimate': earning.get('revenueEstimate'),
+                        'revenue_actual': earning.get('revenueActual'),
+                        'hour': earning.get('hour', 'TBD'),
+                        'quarter': earning.get('quarter'),
+                        'year': earning.get('year')
+                    }
+
+                    enriched_earnings.append(enriched_earning)
+
+                except Exception as e:
+                    logger.warning(f"Could not fetch profile for {symbol}: {e}")
+                    continue
+
+            # Sort by date, then by market cap descending
+            enriched_earnings.sort(key=lambda x: (x['date'], -x['market_cap']))
+
+            logger.info(f"Found {len(enriched_earnings)} earnings (market cap >= ${min_market_cap/1_000_000_000:.1f}B)")
+            return enriched_earnings
+
+        except Exception as e:
+            logger.error(f"Error fetching earnings calendar: {e}")
+            return None