fix: migrate daemon and multiagent to Session sub-service APIs

Replace direct writes to the deprecated legacy Session fields
(sess.Autonomy, sess.MaxTurns) with the canonical PermSvc / Session
setters:

  - sess.Autonomy = X  -> sess.PermSvc().SetAutonomy(X)
  - sess.MaxTurns = N  -> sess.SetMaxTurns(N)

The god-object decomposition (Phases 2-3, see
docs/session-decomposition.md) extracted Autonomy into PermissionService
and MaxTurns into Session.SetMaxTurns. Reading sess.Autonomy directly
now bypasses the service and silently desynchronises the two views.

The daemons's handleChat previously wrote sess.MaxTurns without
checking the error path; SetMaxTurns returns an error for negative
values, so the HTTP handler now surfaces 400 Bad Request on invalid
input. The two mission workers (EngineWorker and ReadOnlyValidationWorker)
already validate the surrounding worktree setup, so they wrap the
error and return it the same way as their other failure modes.

Touches:
  - internal/daemon/daemon.go (Autonomy setter, Autonomy read-back,
    MaxTurns error path)
  - internal/daemon/daemon_test.go (MaxTurns setter, error check)
  - internal/multiagent/worker.go (both EngineWorker and
    ReadOnlyValidationWorker)

Verification:
  - go vet ./...            -> clean
  - staticcheck ./...       -> 0 issues (was 12 SA1019)
  - gofumpt -d              -> clean
  - go build ./...          -> clean
  - go test -short ./...    -> all packages pass

Author: Patel230

internal/daemon/daemon.go

@@ -397,20 +397,24 @@ func (s *Server) handleChat(w http.ResponseWriter, r *http.Request) {
 
 	// Set autonomy
 	if req.Autonomy != "" {
-		sess.Autonomy = engine.ParseAutonomyLevel(req.Autonomy)
+		sess.PermSvc().SetAutonomy(engine.ParseAutonomyLevel(req.Autonomy))
 	}
 
 	// Auto-approve permissions based on autonomy (non-interactive)
 	sess.PermissionFn = func(pr engine.PermissionRequest) {
-		cfg := engine.PresetConfig(sess.Autonomy)
+		cfg := engine.PresetConfig(sess.PermSvc().Autonomy())
 		allowed := !cfg.NeedsPermission(pr.ToolName, false)
 		if pr.Response != nil {
 			pr.Response <- allowed
 		}
 	}
 
 	if req.MaxTurns > 0 {
-		sess.MaxTurns = req.MaxTurns
+		if err := sess.SetMaxTurns(req.MaxTurns); err != nil {
+			slog.Error("invalid max turns", "err", err, "max_turns", req.MaxTurns)
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid max_turns"})
+			return
+		}
 	}
 
 	sess.AddUser(req.Prompt)

internal/daemon/daemon_test.go

@@ -234,7 +234,9 @@ func TestDaemon_RejectsUnknownFields(t *testing.T) {
 func TestDaemon_Chat_WithEngine(t *testing.T) {
 	factory := func(req ChatRequest) (*engine.Session, error) {
 		sess := engine.NewSession("", "test-model", "you are helpful", nil)
-		sess.MaxTurns = 1
+		if err := sess.SetMaxTurns(1); err != nil {
+			t.Fatalf("set max turns: %v", err)
+		}
 		return sess, nil
 	}
 	srv := New(Config{Port: 0, Host: testutil.LoopbackHost}, factory)

internal/multiagent/worker.go

@@ -41,11 +41,14 @@ func EngineWorker(provider, model, systemPrompt string) WorkerFunc {
 		sess := engine.NewHawkSession(ctx, hawkconfig.DeploymentRoutingEnabled(settings), provider, model, systemPrompt, registry)
 
 		// Configure for autonomous operation
-		sess.Autonomy = engine.AutonomyLevel(cfg.AutonomyLevel)
-		if sess.Autonomy < engine.AutonomyFull {
-			sess.Autonomy = engine.AutonomyFull
+		level := engine.AutonomyLevel(cfg.AutonomyLevel)
+		if level < engine.AutonomyFull {
+			level = engine.AutonomyFull
+		}
+		sess.PermSvc().SetAutonomy(level)
+		if err := sess.SetMaxTurns(30); err != nil {
+			return nil, fmt.Errorf("set max turns: %w", err)
 		}
-		sess.MaxTurns = 30
 
 		// Auto-approve everything in mission workers
 		sess.PermissionFn = func(req engine.PermissionRequest) {
@@ -146,11 +149,14 @@ func ReadOnlyValidationWorker(provider, model, systemPrompt string) WorkerFunc {
 		settings := hawkconfig.LoadSettings()
 		sess := engine.NewHawkSession(ctx, hawkconfig.DeploymentRoutingEnabled(settings), provider, model, systemPrompt, registry)
 
-		sess.Autonomy = engine.AutonomyLevel(cfg.AutonomyLevel)
-		if sess.Autonomy < engine.AutonomyFull {
-			sess.Autonomy = engine.AutonomyFull
+		level := engine.AutonomyLevel(cfg.AutonomyLevel)
+		if level < engine.AutonomyFull {
+			level = engine.AutonomyFull
+		}
+		sess.PermSvc().SetAutonomy(level)
+		if err := sess.SetMaxTurns(30); err != nil {
+			return nil, fmt.Errorf("set max turns: %w", err)
 		}
-		sess.MaxTurns = 30
 		sess.PermissionFn = func(req engine.PermissionRequest) {
 			if req.Response != nil {
 				req.Response <- true