refactor(filtering): consolidate task list filters into single strategy registry

Replace the three drifting filter implementations (counter, list loader,
regroup) with one ITaskListFilter strategy per list kind. Counter and list
loader now share the same predicates, so they cannot diverge again. Planning
hierarchy rules (parent-as-context, orphan handling) live in PlanningRules
and are unit-tested via 29 new tests in ClaudeDo.Data.Tests.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Data/Filtering/Filters/ImportantFilter.cs

@@ -0,0 +1,12 @@
+using ClaudeDo.Data.Models;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Filtering.Filters;
+
+public sealed class ImportantFilter : ITaskListFilter
+{
+    public string Id => "smart:important";
+    public bool Matches(TaskEntity t) => t.IsStarred;
+    public bool ShouldCount(TaskEntity t) => t.IsStarred && t.Status != TaskStatus.Done;
+    public bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) => false;
+}

src/ClaudeDo.Data/Filtering/Filters/MyDayFilter.cs

@@ -0,0 +1,12 @@
+using ClaudeDo.Data.Models;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Filtering.Filters;
+
+public sealed class MyDayFilter : ITaskListFilter
+{
+    public string Id => "smart:my-day";
+    public bool Matches(TaskEntity t) => t.IsMyDay;
+    public bool ShouldCount(TaskEntity t) => t.IsMyDay && t.Status != TaskStatus.Done;
+    public bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) => false;
+}

src/ClaudeDo.Data/Filtering/Filters/PlannedFilter.cs

@@ -0,0 +1,12 @@
+using ClaudeDo.Data.Models;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Filtering.Filters;
+
+public sealed class PlannedFilter : ITaskListFilter
+{
+    public string Id => "smart:planned";
+    public bool Matches(TaskEntity t) => t.ScheduledFor != null;
+    public bool ShouldCount(TaskEntity t) => t.ScheduledFor != null && t.Status != TaskStatus.Done;
+    public bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) => false;
+}

src/ClaudeDo.Data/Filtering/Filters/QueuedFilter.cs

@@ -0,0 +1,14 @@
+using ClaudeDo.Data.Models;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Filtering.Filters;
+
+public sealed class QueuedFilter : ITaskListFilter
+{
+    public string Id => "virtual:queued";
+    public bool Matches(TaskEntity t) => t.Status == TaskStatus.Queued;
+    public bool ShouldCount(TaskEntity t) => t.Status == TaskStatus.Queued;
+    public bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) =>
+        PlanningRules.IsPlanningParent(t) &&
+        PlanningRules.HasMatchingChild(t, all, c => c.Status == TaskStatus.Queued);
+}

src/ClaudeDo.Data/Filtering/Filters/ReviewFilter.cs

@@ -0,0 +1,14 @@
+using ClaudeDo.Data.Models;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Filtering.Filters;
+
+public sealed class ReviewFilter : ITaskListFilter
+{
+    public string Id => "virtual:review";
+    public bool Matches(TaskEntity t) =>
+        t.Status == TaskStatus.Done &&
+        t.Worktree is { State: WorktreeState.Active };
+    public bool ShouldCount(TaskEntity t) => Matches(t);
+    public bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) => false;
+}

src/ClaudeDo.Data/Filtering/Filters/RunningFilter.cs

@@ -0,0 +1,14 @@
+using ClaudeDo.Data.Models;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Filtering.Filters;
+
+public sealed class RunningFilter : ITaskListFilter
+{
+    public string Id => "virtual:running";
+    public bool Matches(TaskEntity t) => t.Status == TaskStatus.Running;
+    public bool ShouldCount(TaskEntity t) => t.Status == TaskStatus.Running;
+    public bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) =>
+        PlanningRules.IsPlanningParent(t) &&
+        PlanningRules.HasMatchingChild(t, all, c => c.Status == TaskStatus.Running);
+}

src/ClaudeDo.Data/Filtering/Filters/UserListFilter.cs

@@ -0,0 +1,24 @@
+using ClaudeDo.Data.Models;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Filtering.Filters;
+
+/// <summary>
+/// Filter for any user-defined list. Constructed on demand from the list id —
+/// one instance per list.
+/// </summary>
+public sealed class UserListFilter : ITaskListFilter
+{
+    private readonly string _listId;
+
+    public UserListFilter(string listId)
+    {
+        _listId = listId;
+        Id = $"user:{listId}";
+    }
+
+    public string Id { get; }
+    public bool Matches(TaskEntity t) => t.ListId == _listId;
+    public bool ShouldCount(TaskEntity t) => t.ListId == _listId && t.Status != TaskStatus.Done;
+    public bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) => false;
+}

src/ClaudeDo.Data/Filtering/ITaskListFilter.cs

@@ -0,0 +1,26 @@
+using ClaudeDo.Data.Models;
+
+namespace ClaudeDo.Data.Filtering;
+
+/// <summary>
+/// Strategy that defines which tasks belong to a single list. One implementation
+/// per list kind; consumers (counters, list loader) ask the registry for the
+/// right strategy and never branch on the list id themselves.
+/// </summary>
+public interface ITaskListFilter
+{
+    /// <summary>The list id this filter applies to (e.g. "virtual:queued", "user:abc").</summary>
+    string Id { get; }
+
+    /// <summary>True if <paramref name="t"/> is a primary citizen of this list — appears as a row.</summary>
+    bool Matches(TaskEntity t);
+
+    /// <summary>True if <paramref name="t"/> should be counted in this list's badge.</summary>
+    bool ShouldCount(TaskEntity t);
+
+    /// <summary>
+    /// True if <paramref name="t"/> is shown as a contextual row (not a primary citizen,
+    /// but appears to host children that match). Default: nothing extra.
+    /// </summary>
+    bool MatchesAsContext(TaskEntity t, IReadOnlyList<TaskEntity> all) => false;
+}

src/ClaudeDo.Data/Filtering/PlanningRules.cs

@@ -0,0 +1,27 @@
+using ClaudeDo.Data.Models;
+
+namespace ClaudeDo.Data.Filtering;
+
+/// <summary>
+/// Shared predicates that capture planning-hierarchy semantics. Any new rule
+/// involving parents, children, or planning phases belongs here.
+/// </summary>
+public static class PlanningRules
+{
+    public static bool IsPlanningParent(TaskEntity t) =>
+        t.PlanningPhase != PlanningPhase.None;
+
+    public static bool HasMatchingChild(
+        TaskEntity parent,
+        IReadOnlyList<TaskEntity> all,
+        Func<TaskEntity, bool> childPredicate)
+    {
+        for (var i = 0; i < all.Count; i++)
+        {
+            var c = all[i];
+            if (c.ParentTaskId == parent.Id && childPredicate(c))
+                return true;
+        }
+        return false;
+    }
+}

src/ClaudeDo.Data/Filtering/TaskListFilterRegistry.cs

@@ -0,0 +1,38 @@
+using ClaudeDo.Data.Filtering.Filters;
+
+namespace ClaudeDo.Data.Filtering;
+
+/// <summary>
+/// Resolves a list id (e.g. "virtual:queued", "user:abc") to the filter that
+/// owns its semantics. Smart and virtual filters are singletons; user-list
+/// filters are constructed on demand from the id.
+/// </summary>
+public sealed class TaskListFilterRegistry
+{
+    public const string UserListPrefix = "user:";
+
+    private static readonly IReadOnlyDictionary<string, ITaskListFilter> BuiltIn =
+        new Dictionary<string, ITaskListFilter>(StringComparer.Ordinal)
+        {
+            ["smart:my-day"]    = new MyDayFilter(),
+            ["smart:important"] = new ImportantFilter(),
+            ["smart:planned"]   = new PlannedFilter(),
+            ["virtual:queued"]  = new QueuedFilter(),
+            ["virtual:running"] = new RunningFilter(),
+            ["virtual:review"]  = new ReviewFilter(),
+        };
+
+    /// <summary>
+    /// Resolve a filter for a list id, or null if the id is unknown.
+    /// </summary>
+    public ITaskListFilter? Resolve(string listId)
+    {
+        if (BuiltIn.TryGetValue(listId, out var f)) return f;
+        if (listId.StartsWith(UserListPrefix, StringComparison.Ordinal))
+        {
+            var inner = listId[UserListPrefix.Length..];
+            return string.IsNullOrEmpty(inner) ? null : new UserListFilter(inner);
+        }
+        return null;
+    }
+}