Show ranking capsules and value breakdown in station details

The More info sheet now lists every ranking a station qualifies for, directly under the map and above the price and distance: the same StationLabelBadge the listing rows render, in a flow layout so two or three capsules wrap to a new line rather than truncating at large Dynamic Type.

The rules are not restated. StationRanking defers to StationRecommendationBadge.badge for the Best Value gate, and takes Cheapest and Top as the flags the host list already computed for its own rows, so the sheet cannot award a capsule the row behind it withheld. A host passes one of the two, never both: Stations sends isCheapestInRange, Favourites sends isTopFavourite. No calculation, ranking, eligibility or savings logic changed.

Rename the card heading Best Value to Value breakdown, since the working behind it can end in Costs rather than a saving, and drop the green section tint so the card matches the neutral background used elsewhere in the sheet. The Saves, Break even and Costs capsules and every breakdown row are untouched.

Rename the explanation link to How does FuelBoard calculate value? It names the calculation rather than the feature, of which the Best Value gate is only the last step. The sheet's own title stays short: the full question truncated to 'How does FuelBoard...' as a navigation title at both inline and large display modes, so the row carries the question and the sheet names the topic.

Tests: 269 pass, 5 new covering capsule selection, order and sheet-vs-row agreement on Best Value.

FuelBoard/ContentView.swift

@@ -830,6 +830,10 @@ struct ContentView: View {
                         fuelSavingsAmount: sessionFuelSavingsAmount,
                         savingsBaselineStationName: scaffold.baseline?.name,
                         journeyDiagnostics: journeyDiagnostics(for: station, baseline: scaffold.baseline),
+                        // The same "cheapest in range" test this view gives its
+                        // rows, so the sheet's Cheapest capsule matches the badge on
+                        // the list it was opened from.
+                        isCheapestInRange: station.id == topStationID,
                         isFavourite: favouriteIDs.contains(station.id),
                         onToggleFavourite: { toggleFavourite(station, fuel: selectedFuel) }
                     )