ci(client): source files may not grow past their size baseline

lint:size counts the lines of every source file under client/src, tests
aside. A file may hold 1000 lines; the 24 files that are longer today are
listed in scripts/size-baseline.json with their current length and fail
the check when they grow. --update lowers an entry once a file shrinks
and never raises one, so a long file is split by concern instead of
growing. A baseline that cannot be read or parsed stops the check with
its reason, and --update leaves it as it is. It runs in the client job
next to the reading direction check.

client/scripts/size-baseline.json

@@ -0,0 +1,26 @@
+{
+  "api/client.ts": 1685,
+  "components/Admin/AdminPluginsPanel.tsx": 2274,
+  "components/Budget/CostsPanel.tsx": 2107,
+  "components/Map/MapView.tsx": 1482,
+  "components/Map/MapViewGL.tsx": 2572,
+  "components/Map/RouteCalculator.ts": 1190,
+  "components/PDF/TripPDF.tsx": 1025,
+  "components/Planner/DayPlanSidebar.tsx": 3058,
+  "components/Planner/PlaceFormModal.tsx": 1633,
+  "components/Planner/PlaceInspector.tsx": 1273,
+  "components/Planner/TransportModal.tsx": 1199,
+  "components/Roadtrip/RoadtripSidebar.tsx": 2287,
+  "components/Studio/autoLayout.ts": 1676,
+  "components/Studio/bookTemplates.data.ts": 1279,
+  "components/Studio/TravelElements.tsx": 1745,
+  "mobile/screens/admin/MAdminPluginsPanel.tsx": 2105,
+  "mobile/screens/journey/MJourneyEntrySheet.tsx": 1060,
+  "mobile/screens/trip/sheets/MTransportFormSheet.tsx": 1127,
+  "mobile/screens/trip/tabs/MCostsTab.tsx": 1011,
+  "mobile/screens/trip/tabs/MPackingListTab.tsx": 1017,
+  "pages/atlas/useAtlas.ts": 1246,
+  "pages/LoginPage.tsx": 1340,
+  "pages/tripPlanner/useTripPlanner.ts": 3095,
+  "pages/TripPlannerPage.tsx": 1427
+}