recover: restore untracked work from recovery branch (no Gemini changes)

Recovered files with no Claude→Agent contamination:
- docs/adr/002-task-state-machine.md
- internal/api/logs.go/logs_test.go: task-level log streaming endpoint
- internal/api/validate.go/validate_test.go: POST /api/tasks/validate
- internal/api/server_test.go, storage/db_test.go: expanded test coverage
- scripts/reset-failed-tasks, reset-running-tasks
- web/app.js, index.html, style.css: frontend improvements
- web/test/: active-tasks-tab, delete-button, filter-tabs, sort-tasks tests

Manually applied from server.go diff (skipping Claude→Agent rename):
- taskLogStore field + validateCmdPath field
- DELETE /api/tasks/{id} route + handleDeleteTask
- GET /api/tasks/{id}/logs/stream route
- POST /api/tasks/{id}/resume route + handleResumeTimedOutTask
- handleCancelTask: allow cancelling PENDING/QUEUED tasks directly

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

1 files changed, 52 insertions, 0 deletions

diff --git a/internal/api/logs.go b/internal/api/logs.go
index 0354943..1ba4b00 100644
--- a/internal/api/logs.go
+++ b/internal/api/logs.go
@@ -19,6 +19,12 @@ type logStore interface {
 	GetExecution(id string) (*storage.Execution, error)
 }
 
+// taskLogStore is the minimal storage interface needed by handleStreamTaskLogs.
+type taskLogStore interface {
+	GetExecution(id string) (*storage.Execution, error)
+	GetLatestExecution(taskID string) (*storage.Execution, error)
+}
+
 const maxTailDuration = 30 * time.Minute
 
 var terminalStates = map[string]bool{
@@ -46,6 +52,52 @@ type logContentBlock struct {
 	Input json.RawMessage `json:"input,omitempty"`
 }
 
+// handleStreamTaskLogs streams the latest execution log for a task via SSE.
+// GET /api/tasks/{id}/logs/stream
+func (s *Server) handleStreamTaskLogs(w http.ResponseWriter, r *http.Request) {
+	taskID := r.PathValue("id")
+	exec, err := s.taskLogStore.GetLatestExecution(taskID)
+	if err != nil {
+		http.Error(w, "task not found", http.StatusNotFound)
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("X-Accel-Buffering", "no")
+
+	flusher, ok := w.(http.Flusher)
+	if !ok {
+		http.Error(w, "streaming not supported", http.StatusInternalServerError)
+		return
+	}
+
+	ctx := r.Context()
+
+	if terminalStates[exec.Status] {
+		if exec.StdoutPath != "" {
+			if f, err := os.Open(exec.StdoutPath); err == nil {
+				defer f.Close()
+				var offset int64
+				for _, line := range readNewLines(f, &offset) {
+					select {
+					case <-ctx.Done():
+						return
+					default:
+					}
+					emitLogLine(w, flusher, line)
+				}
+			}
+		}
+	} else if exec.Status == string(task.StateRunning) {
+		tailRunningExecution(ctx, w, flusher, s.taskLogStore, exec)
+		return
+	}
+
+	fmt.Fprintf(w, "event: done\ndata: {}\n\n")
+	flusher.Flush()
+}
+
 // handleStreamLogs streams parsed execution log content via SSE.
 // GET /api/executions/{id}/logs/stream
 func (s *Server) handleStreamLogs(w http.ResponseWriter, r *http.Request) {