Make station price age informational only

The relay's price_updated is the maximum price_last_updated across the grades it maps, so it cannot vouch for the selected grade: stop using it to score, gate or warn about Best Value.

- FuelPriceFreshness is now station-level and display-only: one age per station, fresh/outdated/unknown/invalid, "May be outdated" past 30 days, with future-tolerance and non-finite guards.
- Best Value restores the closest-station-selling-the-selected-fuel baseline and its savings ranking; eligibility gating, eligible-first sorting and the unavailable banner are gone.
- Price age appears in the More info sheet only - no listing-row warnings, no extra banners.
- Copy reverted from "closest eligible station" to "closest station"; stale price-confidence strings removed, "May be outdated" added.
- Dormant per-grade timestamp plumbing removed, and regression tests added for every fuel type, missing/invalid/future stamps and the bundled offline dump.

Shared/FuelPriceWidgetViews.swift

@@ -35,11 +35,6 @@ struct FuelPriceWidgetEntryData {
     let locationSource: String    // "live" | "cached" | "none"
     let unit: DistanceUnit        // user's display unit for distances
     let bestValueResult: FuelSavingsResult? // only populated for the small Best Value face
-    /// Both selected-fuel prices are assessed by the shared freshness policy.
-    var bestValuePriceConfidence: FuelPriceFreshness.ComparisonConfidence = .ineligible
-    /// Candidate-aware warning copy (names the fuel, and the baseline when the
-    /// baseline is the weak link). Falls back to the confidence's own text.
-    var bestValuePriceWarning: String? = nil
 }
 
 /// The widget face, parameterised by family so the app can preview it.
@@ -97,16 +92,10 @@ struct FuelPriceWidgetContent: View {
                 Text(result.headline(compact: true))
                     .font(.title3.weight(.bold))
                     .lineLimit(1)
-                Text(result.status == .baseline ? "your baseline" : "vs closest eligible station")
+                Text(result.status == .baseline ? "your baseline" : "vs closest station")
                     .font(.caption2)
                     .foregroundStyle(.secondary)
                     .lineLimit(1)
-                if let warning = entry.bestValuePriceWarning ?? entry.bestValuePriceConfidence.warningText {
-                    Text(warning)
-                        .font(.caption2)
-                        .foregroundStyle(.orange)
-                        .lineLimit(2)
-                }
             } else if entry.sort == .worthTheDrive {
                 if let price = station.prices[entry.fuel] {
                     FuelStore.priceTextAttributed(price, size: 26, weight: .bold, color: .green)
@@ -116,11 +105,6 @@ struct FuelPriceWidgetContent: View {
                         .font(.caption2)
                         .foregroundStyle(.orange)
                         .lineLimit(2)
-                } else {
-                    Text("Best Value unavailable · price confidence insufficient")
-                        .font(.caption2)
-                        .foregroundStyle(.orange)
-                        .lineLimit(2)
                 }
             } else if let price = station.prices[entry.fuel] {
                 FuelStore.priceTextAttributed(price, size: 26, weight: .bold, color: .green)
@@ -163,9 +147,7 @@ struct FuelPriceWidgetContent: View {
                     .font(.caption2)
                     .foregroundStyle(.secondary)
                 Spacer()
-                Text(entry.sort == .worthTheDrive && entry.bestValuePriceConfidence == .ineligible
-                     ? "price order · Best Value unavailable"
-                     : entry.isFavourites ? "your order"
+                Text(entry.isFavourites ? "your order"
                      : (entry.locationSource == "none" ? "by price" : "near you"))
                     .font(.caption2)
                     .foregroundStyle(.secondary)