refactor: collapse single-implementation interfaces

Nine interfaces had exactly one implementation and no test double — they existed
only to be named twice in a DI registration: IFindingsStore, IFindingsStoreLocator,
IPrimeScheduleSignal, IRefineRunner, IWeekReportService, IMergeCoordinator,
IMissionControlPane, IOnlineLoginService, ITaskListFilter. Consumers now depend on
the concrete type; the DTO records that shared those files moved next to their
implementation. IInteractiveLaunchSpecService stays — it carries 54 lines of
contract documentation, which is not ceremony.

IMergeCoordinator in particular had a redundant null object: MergeCoordinator with
a null Handler already no-ops, and every test used the real class with Handler set.

Filtering/ collapses from 8 files to 1. ITaskListFilter and TaskListFilterBase were
a double abstraction over four predicates, with MatchesAsContext => false declared
in both. SmartFlagFilter also compiled its expression twice (its own _flag plus the
inherited Matches cache) — it now uses the cache.

StaticTokenAuthProvider was in src but production uses ZitadelAuthProvider; it is
a test double, so it moves to the test project. Its own test goes away with it.

src/ClaudeDo.Worker/Program.cs

@@ -67,7 +67,7 @@ builder.Services.AddDbContextFactory<ClaudeDoDbContext>(opt =>
 builder.Services.AddSingleton(cfg);
 builder.Services.AddSingleton<AttachmentStore>();
 // Singleton so the always-on and in-task MCP servers share the same index write lock.
-builder.Services.AddSingleton<IFindingsStore, FindingsStore>();
+builder.Services.AddSingleton<FindingsStore>();
 builder.Services.AddHostedService<StaleTaskRecovery>();
 builder.Services.AddHostedService<OrphanRecovery>();
 builder.Services.AddHostedService<AttachmentOrphanRecovery>();
@@ -140,7 +140,7 @@ builder.Services.AddSingleton<OverrideSlotService>();
 builder.Services.AddSingleton<IClaudeHistoryReader>(_ =>
     new ClaudeHistoryReader(Path.Combine(
         Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".claude", "projects")));
-builder.Services.AddSingleton<IWeekReportService, WeekReportService>();
+builder.Services.AddSingleton<WeekReportService>();
 
 // Usage
 builder.Services.AddSingleton<ITranscriptUsageReader, TranscriptUsageReader>();
@@ -154,14 +154,13 @@ builder.Services.AddSingleton<TokenTrackerService>();
 // Prime Claude
 builder.Services.AddSingleton<IPrimeClock, PrimeClock>();
 builder.Services.AddSingleton<PrimeScheduleSignal>();
-builder.Services.AddSingleton<IPrimeScheduleSignal>(sp => sp.GetRequiredService<PrimeScheduleSignal>());
 builder.Services.AddSingleton<IPrimeRunner, PrimeRunner>();
 builder.Services.AddSingleton(PrimeSchedulerOptions.Default);
 builder.Services.AddSingleton<IPrimeBroadcaster>(sp => sp.GetRequiredService<HubBroadcaster>());
 builder.Services.AddHostedService<PrimeScheduler>();
 
 // Refine
-builder.Services.AddSingleton<IRefineRunner, RefineRunner>();
+builder.Services.AddSingleton<RefineRunner>();
 builder.Services.AddSingleton<IRefineBroadcaster>(sp => sp.GetRequiredService<HubBroadcaster>());
 
 // "Continue on session limit reset" toggle — depends on UsageState, registered below.
@@ -199,7 +198,7 @@ builder.Services.AddScoped<ClaudeDoDbContext>(sp =>
 builder.Services.AddScoped<TaskRepository>();
 builder.Services.AddScoped<ListRepository>();
 builder.Services.AddScoped<PlanningMcpService>();
-builder.Services.AddScoped<IFindingsStoreLocator, FindingsStoreLocator>();
+builder.Services.AddScoped<FindingsStoreLocator>();
 builder.Services.AddScoped<TaskRunFindingsMcpTools>();
 builder.Services.AddMcpServer()
     .WithHttpTransport()
@@ -339,8 +338,8 @@ if (cfg.ExternalMcpPort > 0)
     externalBuilder.Services.AddSingleton(app.Services.GetRequiredService<AttachmentStore>());
     externalBuilder.Services.AddScoped<TaskAttachmentRepository>();
     externalBuilder.Services.AddScoped<AttachmentMcpTools>();
-    externalBuilder.Services.AddSingleton<IFindingsStore>(app.Services.GetRequiredService<IFindingsStore>());
-    externalBuilder.Services.AddScoped<IFindingsStoreLocator, FindingsStoreLocator>();
+    externalBuilder.Services.AddSingleton(app.Services.GetRequiredService<FindingsStore>());
+    externalBuilder.Services.AddScoped<FindingsStoreLocator>();
     externalBuilder.Services.AddScoped<FindingsMcpTools>();
     externalBuilder.Services.AddMcpServer()
         .WithHttpTransport()