feat(worker): add TranscriptUsageReader for per-model token usage

Aggregates ~/.claude/projects/**/*.jsonl assistant messages by date/model/
scope (ClaudeDo worktree-or-sandbox cwd vs Other), deduped by requestId
(falls back to message.id), with a per-file length+mtime cache so repeat
calls skip unchanged files.

src/ClaudeDo.Worker/Program.cs

@@ -19,6 +19,8 @@ using ClaudeDo.Worker.Refine;
 using ClaudeDo.Worker.Report;
 using ClaudeDo.Worker.Report.Interfaces;
 using ClaudeDo.Worker.Skills;
+using ClaudeDo.Worker.Usage;
+using ClaudeDo.Worker.Usage.Interfaces;
 using ClaudeDo.Worker.Worktrees;
 using Microsoft.EntityFrameworkCore;
 using Serilog;
@@ -122,6 +124,9 @@ builder.Services.AddSingleton<IClaudeHistoryReader>(_ =>
         Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".claude", "projects")));
 builder.Services.AddSingleton<IWeekReportService, WeekReportService>();
 
+// Usage
+builder.Services.AddSingleton<ITranscriptUsageReader, TranscriptUsageReader>();
+
 // Prime Claude
 builder.Services.AddSingleton<IPrimeClock, PrimeClock>();
 builder.Services.AddSingleton<PrimeScheduleSignal>();