feat(Phase4): add file changes for changestats executor wiring

Files changed: CLAUDE.md, internal/api/changestats.go,
internal/executor/executor.go, internal/executor/executor_test.go,
internal/task/changestats.go (new)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/internal/executor/executor.go b/internal/executor/executor.go
index 7674fe6..fd37c33 100644
--- a/internal/executor/executor.go
+++ b/internal/executor/executor.go
@@ -29,6 +29,7 @@ type Store interface {
 	UpdateTaskSummary(taskID, summary string) error
 	AppendTaskInteraction(taskID string, interaction task.Interaction) error
 	UpdateTaskAgent(id string, agent task.AgentConfig) error
+	UpdateExecutionChangestats(execID string, stats *task.Changestats) error
 }
 
 // LogPather is an optional interface runners can implement to provide the log
@@ -352,6 +353,13 @@ func (p *Pool) handleRunResult(ctx context.Context, t *task.Task, exec *storage.
 			p.logger.Error("failed to update task summary", "taskID", t.ID, "error", summaryErr)
 		}
 	}
+	if exec.StdoutPath != "" {
+		if cs := task.ParseChangestatFromFile(exec.StdoutPath); cs != nil {
+			if csErr := p.store.UpdateExecutionChangestats(exec.ID, cs); csErr != nil {
+				p.logger.Error("failed to store changestats", "execID", exec.ID, "error", csErr)
+			}
+		}
+	}
 	if updateErr := p.store.UpdateExecution(exec); updateErr != nil {
 		p.logger.Error("failed to update execution", "error", updateErr)
 	}