feat: Add comprehensive trading days validation and record count analysis

- Add trading days validation to check expected vs actual data points per year
- Implement calculate_expected_trading_days() accounting for weekends and Czech holidays
- Add validate_trading_days_count() with discrepancy analysis and severity classification
- Integrate trading days validation into main validation workflow
- Add record count analysis by time periods (week, month, quarter, half year, year)
- Implement get_record_counts_by_period() with detailed breakdowns
- Add --record-counts CLI command for standalone period analysis
- Enhance format_validation_text() to display trading days and record count information
- Update data quality scoring to include trading days compliance
- Add comprehensive JSON output support for all new validation features

Trading Days Validation:
- Calculates expected trading days excluding weekends and Czech holidays
- Compares actual data points against expected counts
- Provides discrepancy analysis with severity levels (ok, minor, moderate, severe)
- Shows data completeness percentage

Record Count Analysis:
- Breaks down data by multiple time periods simultaneously
- Supports week-by-week, monthly, quarterly, half-yearly, and yearly counts
- Handles leap years and varying month lengths correctly
- Provides both summary and detailed views

Integration Features:
- Seamlessly integrated with existing price change and gap validation
- Enhanced data quality scoring considers all validation aspects
- Comprehensive JSON schema for programmatic consumption
- Backward compatible with existing validation commands

Usage Examples:
  python src/cli.py --validate --currency USD --year 2025  # Shows all validations
  python src/cli.py --record-counts --currency USD --year 2025  # Period breakdown only
  python src/cli.py --validate --currency EUR --json  # Full validation in JSON

Quality Assurance:
- ✅ Pyright type checking: 0 errors, 0 warnings
- ✅ Syntax validation: No compilation errors
- ✅ Functional testing: All features working correctly
- ✅ Czech holiday integration: Proper weekend/holiday exclusion
- ✅ Leap year handling: Correctly accounts for 366-day years

src/cli.py

@@ -202,6 +202,11 @@ def main():
         action="store_true",
         help="Validuje data pro měnu nebo všechny měny. Zkontroluje konzistenci kurzů a detekuje možné chyby.",
     )
+    parser.add_argument(
+        "--record-counts",
+        action="store_true",
+        help="Zobrazí počet záznamů podle časových období (týden, měsíc, čtvrtletí, pololetí, rok).",
+    )
     parser.add_argument(
         "--change-threshold",
         type=float,
@@ -289,6 +294,67 @@ def main():
             else:
                 text_output = data_validator.format_validation_text(results)
                 print(text_output)
+    elif args.record_counts:
+        # Record counts command
+        if not args.currency:
+            print(
+                "Chyba: Pro --record-counts je nutné zadat měnu pomocí -c/--currency."
+            )
+            sys.exit(1)
+
+        debug_print(f"Získávám počty záznamů pro měnu {args.currency}...")
+        record_counts = data_validator.get_record_counts_by_period(
+            args.currency, args.year
+        )
+
+        if args.json:
+            output_json({"currency": args.currency, "record_counts": record_counts})
+        else:
+            print(f"Record Counts for {args.currency}:")
+            print("=" * 50)
+
+            for year_key, periods in record_counts.items():
+                print(f"\nYear {year_key}:")
+                print(f"  Total records: {periods.get('year', 0)}")
+
+                # Half years
+                half_years = periods.get("half_year", {})
+                if half_years:
+                    print(
+                        f"  Half years: H1={half_years.get('H1', 0)}, H2={half_years.get('H2', 0)}"
+                    )
+
+                # Quarters
+                quarters = periods.get("quarter", {})
+                if quarters:
+                    quarter_str = ", ".join(
+                        [f"Q{q}={quarters.get(f'Q{q}', 0)}" for q in range(1, 5)]
+                    )
+                    print(f"  Quarters: {quarter_str}")
+
+                # Months
+                months = periods.get("month", {})
+                if months:
+                    month_list = []
+                    for month in range(1, 13):
+                        month_key = f"{month:02d}"
+                        count = months.get(month_key, 0)
+                        month_list.append(f"{month}={count}")
+                    print(f"  Months: {', '.join(month_list)}")
+
+                # Weeks summary
+                weeks = periods.get("week", {})
+                if weeks:
+                    total_weeks = len(weeks)
+                    if total_weeks <= 10:
+                        week_list = sorted([f"{w}={weeks[w]}" for w in weeks.keys()])
+                        print(f"  Weeks: {', '.join(week_list)}")
+                    else:
+                        sample_weeks = sorted(list(weeks.keys())[:5])
+                        week_sample = [f"{w}={weeks[w]}" for w in sample_weeks]
+                        print(
+                            f"  Weeks: {', '.join(week_sample)}... ({total_weeks} total weeks)"
+                        )
     elif args.year:
         # Validation command
         base_threshold = args.change_threshold