Add favourite price-drop Check now action

BACKLOG.md

@@ -106,6 +106,19 @@ Status: TODO / IN PROGRESS / DONE / BLOCKED.
   scene (CPListTemplate) for navigation deep-links.
 - [ ] **Alert region tuning** — make alert trigger radius + dedup window
   user-configurable (currently fixed 300 m trigger / 1 per station per hour).
+- [ ] **Price-drop alerts: threshold control + Check now** — keep the current
+  cache-first / 12 h refresh policy, but add a per-alert sensitivity control
+  for favourite price-drop alerts instead of a fetch-frequency slider. Scope:
+  `Minimum change` picker (e.g. 0.5p / 1.0p / 2.0p), plus a `Check now`
+  action in the Alerts tab that forces a fetch and immediately re-evaluates the
+  cheapest-favourite alert. Copy should set expectation honestly: standard
+  mode checks when FuelBoard refreshes prices (up to twice daily).
+- [ ] **Price-drop alerts: optional frequent-check mode** — if the app ever
+  relaxes the current "twice daily max" data policy, expose this as a clearly
+  separate mode rather than a freeform frequency slider. Example framing:
+  `Standard` (current behaviour) vs `Frequent` (best-effort extra checks),
+  with conservative caps (e.g. every 4–6 h, not hourly) and copy that does not
+  promise exact timing under iOS background scheduling.
 - [ ] **Pull-to-refresh spinner state** — surface refresh in-flight state
   (currently `refreshable` fires but no visible progress in the row list).
 - [x] **Offline first-run** — bundled REAL 8,022-station dump (`FuelBoardDump`,
@@ -135,6 +148,12 @@ Status: TODO / IN PROGRESS / DONE / BLOCKED.
   trend, after the Trends UI lands (one-kind rule preserved).
 - [ ] **Price alerts for a specific station** — notify when a starred station's
   price drops below a user threshold.
+- [ ] **Price-drop alerts: mode = Cheapest favourite / All favourites** — keep
+  `Cheapest favourite` as the default low-noise mode, but explore an optional
+  `All favourites` mode for one fuel. Guardrails if built: threshold required,
+  per-station dedupe based on last-alerted price (not just time), and combine
+  multiple drops from one refresh into a single summary notification rather
+  than one alert per station.
 - [ ] **Share sheet** — share "Cheapest Unleaded near me" as text/image card.
 - [ ] **Watch app** — glanceable cheapest-price complication (WatchKit + shared
   app-group store; watch target would need to be added to the project).

FuelBoard/AlertsView.swift

@@ -32,6 +32,7 @@ struct AlertsView: View {
     let distanceUnit: DistanceUnit
     let monitoredCount: Int
     let lastAlert: String?
+    let onCheckFavouriteDropNow: () -> Void
 
     /// The Stations-tab search distance shown in the user's unit, e.g.
     /// "5 miles" or "8 km" — for the "Follow search" rows.
@@ -139,6 +140,8 @@ struct AlertsView: View {
                             Text(fuel.displayName).tag(fuel)
                         }
                     }
+                    Button("Check now", action: onCheckFavouriteDropNow)
+                        .disabled(!favouriteDropEnabled)
                 } header: {
                     Text("Price-drop alerts")
                 } footer: {

FuelBoard/ContentView.swift

@@ -623,7 +623,10 @@ struct ContentView: View {
             stationLimit: stationLimit,
             distanceUnit: distanceUnit,
             monitoredCount: monitor.monitoredStationIDs.count,
-            lastAlert: monitor.lastAlert
+            lastAlert: monitor.lastAlert,
+            onCheckFavouriteDropNow: {
+                Task { await refresh(force: true) }
+            }
         )
     }