feat(worker): expose usage/model-usage hub surface and persist run model

Adds GetUsageSnapshot/GetModelUsage/GetTaskUsage to WorkerHub (backed by a
shared UsageSnapshotBuilder), a UsageUpdated broadcast fired after every
UsageMonitorService poll cycle, and records the resolved model on each
task_runs row so per-model/per-task usage can be reported from history.

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -17,6 +17,8 @@ using ClaudeDo.Worker.Report;
 using ClaudeDo.Worker.Report.Interfaces;
 using ClaudeDo.Worker.Skills;
 using ClaudeDo.Worker.State;
+using ClaudeDo.Worker.Usage;
+using ClaudeDo.Worker.Usage.Interfaces;
 using ClaudeDo.Worker.Worktrees;
 using System.Text.Json;
 using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
@@ -103,6 +105,49 @@ public record OnlineInboxConfigInput(
     string Scopes,
     string RedirectUri);
 
+public record UsageLimitDto(
+    string Kind,
+    string Group,
+    double Percent,
+    string Severity,
+    DateTimeOffset? ResetsAt,
+    string? ScopeModelDisplayName,
+    bool IsActive);
+
+public record UsageSnapshotDto(
+    double? FiveHourPercent,
+    DateTimeOffset? FiveHourResetsAt,
+    double? SevenDayPercent,
+    DateTimeOffset? SevenDayResetsAt,
+    IReadOnlyList<UsageLimitDto> Limits,
+    int FiveHourThresholdPct,
+    int SevenDayThresholdPct,
+    bool IsGateBlocked,
+    string? GateReason,
+    DateTime? FetchedAtUtc,
+    bool IsStale,
+    string? LastError);
+
+public record ModelUsageRowDto(
+    DateOnly Date,
+    string Model,
+    string Scope,
+    long InputTokens,
+    long OutputTokens,
+    long CacheReadTokens,
+    long CacheCreationTokens,
+    int Messages);
+
+public record TaskUsageRowDto(
+    string TaskId,
+    string TaskTitle,
+    string ListId,
+    string ListName,
+    string? Model,
+    int Runs,
+    long TokensIn,
+    long TokensOut);
+
 public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
 {
     private static readonly string Version =
@@ -136,6 +181,8 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
     private readonly IInteractiveLaunchSpecService? _interactiveLaunchSpec;
     private readonly WorktreeManager? _worktreeManager;
     private readonly Data.Git.GitService? _git;
+    private readonly UsageSnapshotBuilder? _usageSnapshotBuilder;
+    private readonly ITranscriptUsageReader? _usageReader;
 
     public WorkerHub(
         QueueService queue,
@@ -165,7 +212,9 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         LogRingBuffer? logBuffer = null,
         IInteractiveLaunchSpecService? interactiveLaunchSpec = null,
         WorktreeManager? worktreeManager = null,
-        Data.Git.GitService? git = null)
+        Data.Git.GitService? git = null,
+        UsageSnapshotBuilder? usageSnapshotBuilder = null,
+        ITranscriptUsageReader? usageReader = null)
     {
         _queue = queue;
         _waker = waker;
@@ -195,6 +244,8 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         _interactiveLaunchSpec = interactiveLaunchSpec;
         _worktreeManager = worktreeManager;
         _git = git;
+        _usageSnapshotBuilder = usageSnapshotBuilder;
+        _usageReader = usageReader;
     }
 
     // Persistence boundary for the session_skills JSON-array columns (task/list/global).
@@ -978,4 +1029,65 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         _onlineTokenStore.Clear();
     }
 #pragma warning restore CA1416
+
+    public Task<UsageSnapshotDto> GetUsageSnapshot() => HubGuard(() =>
+    {
+        if (_usageSnapshotBuilder is null)
+            throw new InvalidOperationException("Usage snapshot builder is not configured.");
+        return _usageSnapshotBuilder.BuildAsync(Context.ConnectionAborted);
+    });
+
+    public Task<IReadOnlyList<ModelUsageRowDto>> GetModelUsage(DateOnly from, DateOnly to) => HubGuard(async () =>
+    {
+        if (_usageReader is null)
+            throw new InvalidOperationException("Transcript usage reader is not configured.");
+        var rows = await _usageReader.ReadAsync(from, to, Context.ConnectionAborted);
+        return (IReadOnlyList<ModelUsageRowDto>)rows
+            .Select(r => new ModelUsageRowDto(
+                r.Date, r.Model, r.Scope == UsageScope.ClaudeDo ? "claudedo" : "other",
+                r.InputTokens, r.OutputTokens, r.CacheReadTokens, r.CacheCreationTokens, r.Messages))
+            .ToList();
+    });
+
+    public async Task<IReadOnlyList<TaskUsageRowDto>> GetTaskUsage(DateOnly from, DateOnly to)
+    {
+        var fromDt = from.ToDateTime(TimeOnly.MinValue);
+        var toDt = to.ToDateTime(TimeOnly.MaxValue);
+
+        await using var ctx = await _dbFactory.CreateDbContextAsync(Context.ConnectionAborted);
+        var runs = await ctx.TaskRuns
+            .Where(r => r.StartedAt != null && r.StartedAt >= fromDt && r.StartedAt <= toDt)
+            .ToListAsync(Context.ConnectionAborted);
+
+        if (runs.Count == 0) return Array.Empty<TaskUsageRowDto>();
+
+        var taskIds = runs.Select(r => r.TaskId).Distinct().ToList();
+        var tasks = await ctx.Tasks.Where(t => taskIds.Contains(t.Id)).ToListAsync(Context.ConnectionAborted);
+        var taskById = tasks.ToDictionary(t => t.Id);
+
+        var listIds = tasks.Select(t => t.ListId).Distinct().ToList();
+        var lists = await ctx.Lists.Where(l => listIds.Contains(l.Id)).ToDictionaryAsync(l => l.Id, Context.ConnectionAborted);
+
+        return runs
+            .Where(r => taskById.ContainsKey(r.TaskId))
+            .GroupBy(r => r.TaskId)
+            .Select(g =>
+            {
+                var task = taskById[g.Key];
+                var listName = lists.TryGetValue(task.ListId, out var list) ? list.Name : "";
+                var latestModel = g.OrderByDescending(r => r.StartedAt).First().Model;
+                return new TaskUsageRowDto(
+                    task.Id,
+                    task.Title,
+                    task.ListId,
+                    listName,
+                    latestModel,
+                    g.Count(),
+                    g.Sum(r => (long)(r.TokensIn ?? 0)),
+                    g.Sum(r => (long)(r.TokensOut ?? 0)));
+            })
+            .OrderByDescending(r => r.TokensIn + r.TokensOut)
+            .Take(100)
+            .ToList();
+    }
 }