Route Explorer: unified per-leg load card + multi-leg fan-out

Single ConnectionLoadDetailView is now the universal detail screen for
both Find Connections (1+ legs) and Where Can I Go (single-leg). For
multi-stop connections it fetches each leg's load in parallel via
withTaskGroup so the slowest carrier doesn't block the rest. Each leg
card shows airline + flight + IATAs + airport names + aircraft + an
open/standby summary, with a "Full details" drill-down to
FlightLoadDetailView for waitlists/passenger lists.

Bug fixes along the way:
- Empty origin/destination in carrier API URLs (HTTP 400 from AA): the
  4 separate @State vars feeding .sheet(item:) raced — sheet captured
  empty strings before the other writes settled. Bundled into one
  Identifiable RouteLoadDetailRequest / ConnectionLoadRequest so updates
  are atomic.
- Flight numbers rendered with locale separators ("AA 6,380", "3,189").
  Text("\(int)") resolves to the LocalizedStringKey initializer; switched
  to Text(verbatim:).
- "Load data not available for {airline}" was misleading when the
  airline IS supported but a specific flight has no data. Reworded to
  flight-scoped copy.
- AA fetcher had no logging — added URL/status/body/keys diagnostics
  matching the UA pattern.

UI cleanup:
- DepartureLegRow: big IATAs on their own row, full airport names on a
  middle-truncated subtitle, aircraft pill single-line tail-truncated.
- LegSummary (ConnectionRow): airport-name subtitle line below
  times+IATAs row.
- airportName priority: bundled airports.json first ("Dallas-Fort
  Worth") over the route-explorer appendix ("Dallas Dallas/Fort Worth
  Intl") which truncated to garbage.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Flights.xcodeproj/project.pbxproj

@@ -45,6 +45,7 @@
 		RE4400004444000044440001 /* WhereToGoView.swift in Sources */ = {isa = PBXBuildFile; fileRef = RE4400004444000044440002 /* WhereToGoView.swift */; };
 		RE5500005555000055550001 /* IATAAirportPicker.swift in Sources */ = {isa = PBXBuildFile; fileRef = RE5500005555000055550002 /* IATAAirportPicker.swift */; };
 		RE6600006666000066660001 /* ConnectionRow.swift in Sources */ = {isa = PBXBuildFile; fileRef = RE6600006666000066660002 /* ConnectionRow.swift */; };
+		RE7700007777000077770001 /* ConnectionLoadDetailView.swift in Sources */ = {isa = PBXBuildFile; fileRef = RE7700007777000077770002 /* ConnectionLoadDetailView.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -87,6 +88,7 @@
 		RE4400004444000044440002 /* WhereToGoView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WhereToGoView.swift; sourceTree = "<group>"; };
 		RE5500005555000055550002 /* IATAAirportPicker.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IATAAirportPicker.swift; sourceTree = "<group>"; };
 		RE6600006666000066660002 /* ConnectionRow.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConnectionRow.swift; sourceTree = "<group>"; };
+		RE7700007777000077770002 /* ConnectionLoadDetailView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConnectionLoadDetailView.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -114,6 +116,7 @@
 				BB1100001111000011110006 /* FlightLoadDetailView.swift */,
 				RE3300003333000033330002 /* RoutePlannerView.swift */,
 				RE4400004444000044440002 /* WhereToGoView.swift */,
+				RE7700007777000077770002 /* ConnectionLoadDetailView.swift */,
 				AA5555555555555555555555 /* Styles */,
 				AA6666666666666666666666 /* Components */,
 			);
@@ -310,6 +313,7 @@
 				RE4400004444000044440001 /* WhereToGoView.swift in Sources */,
 				RE5500005555000055550001 /* IATAAirportPicker.swift in Sources */,
 				RE6600006666000066660001 /* ConnectionRow.swift in Sources */,
+				RE7700007777000077770001 /* ConnectionLoadDetailView.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};