refactor: extract interfaces to Interfaces folders and consolidate filters

Move interface declarations into per-area Interfaces/ subfolders, merge the
small task-list filter classes into StatusFilter/SmartFlagFilter, and simplify
related services, converters and hub DTO handling.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/ClaudeDo.Worker/Prime/Interfaces/IPrimeBroadcaster.cs

@@ -0,0 +1,6 @@
+namespace ClaudeDo.Worker.Prime;
+
+public interface IPrimeBroadcaster
+{
+    Task PrimeFiredAsync(Guid scheduleId, bool success, string message, DateTimeOffset firedAt);
+}

src/ClaudeDo.Worker/Prime/Interfaces/IPrimeClock.cs

@@ -0,0 +1,2 @@
+namespace ClaudeDo.Worker.Prime;
+public interface IPrimeClock { DateTimeOffset Now { get; } }

src/ClaudeDo.Worker/Prime/Interfaces/IPrimeRunner.cs

@@ -0,0 +1,8 @@
+namespace ClaudeDo.Worker.Prime;
+
+public interface IPrimeRunner
+{
+    Task<PrimeRunOutcome> FireAsync(PrimeScheduleDto schedule, CancellationToken ct);
+}
+
+public sealed record PrimeRunOutcome(bool Success, string Message);

src/ClaudeDo.Worker/Prime/Interfaces/IPrimeScheduleSignal.cs

@@ -0,0 +1,6 @@
+namespace ClaudeDo.Worker.Prime;
+public interface IPrimeScheduleSignal
+{
+    void Signal();
+    CancellationToken CurrentToken { get; }
+}