feat: improve planning engine travel handling, itinerary reordering, and scenario planners

Add TravelInfo initializers and city normalization helpers to fix repeat
city-pair disambiguation. Improve drag-and-drop reordering with segment
index tracking and source-row-aware zone calculation. Enhance all five
scenario planners with better next-day departure handling and travel
segment placement. Add comprehensive tests across all planners.

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

SportsTimeTests/Planning/ScenarioBPlannerTests.swift

@@ -297,6 +297,49 @@ struct ScenarioBPlannerTests {
         // May also fail if no valid date ranges, which is acceptable
     }
 
+    @Test("plan: explicit date range with out-of-range selected game returns dateRangeViolation")
+    func plan_explicitDateRange_selectedGameOutsideRange_returnsDateRangeViolation() {
+        let baseDate = Date()
+        let rangeStart = baseDate
+        let rangeEnd = baseDate.addingTimeInterval(86400 * 3)
+        let outOfRangeDate = baseDate.addingTimeInterval(86400 * 10)
+
+        let stadium = makeStadium(id: "stadium1", city: "New York", coordinate: nycCoord)
+        let selectedGame = makeGame(id: "outside-anchor", stadiumId: "stadium1", dateTime: outOfRangeDate)
+
+        let prefs = TripPreferences(
+            planningMode: .dateRange,
+            sports: [.mlb],
+            mustSeeGameIds: ["outside-anchor"],
+            startDate: rangeStart,
+            endDate: rangeEnd,
+            leisureLevel: .moderate,
+            lodgingType: .hotel,
+            numberOfDrivers: 1
+        )
+
+        let request = PlanningRequest(
+            preferences: prefs,
+            availableGames: [selectedGame],
+            teams: [:],
+            stadiums: ["stadium1": stadium]
+        )
+
+        let result = planner.plan(request: request)
+
+        guard case .failure(let failure) = result else {
+            Issue.record("Expected date range violation when selected game is outside explicit range")
+            return
+        }
+
+        guard case .dateRangeViolation(let violatingGames) = failure.reason else {
+            Issue.record("Expected .dateRangeViolation, got \(failure.reason)")
+            return
+        }
+
+        #expect(Set(violatingGames.map { $0.id }) == ["outside-anchor"])
+    }
+
     // MARK: - Specification Tests: Arrival Time Validation
 
     @Test("plan: uses arrivalBeforeGameStart validator")