feat: introduce reusable app lists for rules

- AppList @Model with launch migration from legacy inline selections
  (rules with identical selections share one list; idempotent)
- rules point at one app list; Block/Allow Only belongs to the rule and
  is offered only in the Schedule editor (limit kinds sanitize to Block)
- app-list picker sheet (select / create / edit / delete with in-use
  protection) replaces the per-rule selection sheet
- Hard Mode locks app-list editing while any hard rule is blocking
- SwiftData stability: relationships are only wired between managed
  models, and unit tests share one in-memory container (fresh context +
  data wipe per test) — per-test container creation trapped
  intermittently inside SwiftData

OpenAppLockTests/RuleModelTests.swift

@@ -47,11 +47,7 @@ struct RuleModelTests {
 
     @Test("Rules persist and fetch through SwiftData")
     func persistence() throws {
-        let container = try ModelContainer(
-            for: BlockingRule.self,
-            configurations: ModelConfiguration(isStoredInMemoryOnly: true)
-        )
-        let context = container.mainContext
+        let context = try makeInMemoryContext()
         let rule = BlockingRule(
             name: "Deep Sleep", hardMode: true,
             days: Weekday.everyDay, startMinutes: 22 * 60, endMinutes: 6 * 60
@@ -83,7 +79,11 @@ struct RuleDraftTests {
     }
 
     @Test("Draft → rule → draft round-trips every field")
-    func roundTrip() {
+    func roundTrip() throws {
+        let context = try makeInMemoryContext()
+        let list = AppList(name: "Distractions", selectionCount: 3)
+        context.insert(list)
+
         var draft = RuleDraft(kind: .schedule)
         draft.name = "Locked In"
         draft.days = Weekday.everyDay
@@ -92,16 +92,18 @@ struct RuleDraftTests {
         draft.hardMode = true
         draft.blockAdultContent = true
         draft.selectionMode = .allowOnly
-        draft.selectionCount = 3
+        draft.appList = list
 
-        let rule = draft.makeRule()
+        let rule = draft.insertRule(into: context)
         #expect(rule.blockAdultContent)
         #expect(RuleDraft(rule: rule) == draft)
     }
 
     @Test("Applying a draft updates an existing rule")
-    func applyToExisting() {
+    func applyToExisting() throws {
+        let context = try makeInMemoryContext()
         let rule = BlockingRule(name: "Old Name")
+        context.insert(rule)
         var draft = RuleDraft(rule: rule)
         draft.name = "New Name"
         draft.hardMode = true