session: inject bus/log/audit into Agent (prep for Submit move)

Agent now holds all dependencies needed to run turns independently:
bus, log, auditLog, sessionID, startupMessages, readPlanStep, saveSession.
emit() moved to Agent. Session no longer owns startupMessages/readPlanStep.

session/agent.go

@@ -5,7 +5,9 @@ import (
 	"sync"
 	"sync/atomic"
 
+	"github.com/simonfxr/pubsub"
 	"ollie/backend"
+	olog "ollie/log"
 	"ollie/tools"
 )
 
@@ -39,6 +41,15 @@ type Agent struct {
 	stateMu  sync.RWMutex
 	changeMu sync.Mutex
 	changeCond *sync.Cond
+
+	// Injected session-level dependencies (set at creation, stable for agent lifetime).
+	bus            *pubsub.Bus
+	log            *olog.Logger
+	auditLog       *olog.Logger
+	sessionID      string       // the owning session's ID
+	startupMessages []string
+	readPlanStep   func() string
+	saveSession    func()       // trigger debounced persistence
 }
 
 // Backend returns the active backend from the runtime.
@@ -151,6 +162,11 @@ func (ag *Agent) InitCond() {
 	ag.changeCond = sync.NewCond(&ag.changeMu)
 }
 
+// emit publishes an event on the agent's bus.
+func (ag *Agent) emit(ev Event) {
+	ag.bus.Publish("event", ev)
+}
+
 // CWD returns the agent's working directory.
 func (ag *Agent) Cwd() string {
 	ag.stateMu.RLock()

session/core_test.go

@@ -865,7 +865,7 @@ func TestSubmit_BackendError(t *testing.T) {
 
 func TestSubmit_StartupMessages(t *testing.T) {
 	c := newCore(t, nil, nil)
-	c.startupMessages = []string{"startup msg 1", "startup msg 2"}
+	c.r.startupMessages = []string{"startup msg 1", "startup msg 2"}
 	evs := collectEvents(context.Background(), c, "hello")
 	found := 0
 	for _, s := range byRole(evs, "info") {
@@ -876,7 +876,7 @@ func TestSubmit_StartupMessages(t *testing.T) {
 	if found != 2 {
 		t.Errorf("startup messages: found %d info events; want 2; got: %v", found, byRole(evs, "info"))
 	}
-	if c.startupMessages != nil {
+	if c.r.startupMessages != nil {
 		t.Error("startupMessages not cleared after first turn")
 	}
 }

session/session.go

@@ -320,11 +320,9 @@ type Session struct {
 	r            *Agent
 	log             *olog.Logger
 	sessionsDir     string
-	readPlanStep    func() string
 	listHandlers    map[string]func() []string
 	turnError       func(ctx context.Context, errType, errMsg string) HookResult // overridable for tests
 	remote          string   // SSH target for remote execution
-	startupMessages []string
 	mu              sync.RWMutex
 	auditLog        *olog.Logger
 
@@ -455,30 +453,36 @@ func New(cfg Config) *Session {
 		log = olog.NewWriter("core", olog.LevelError+1, io.Discard, io.Discard)
 	}
 
+	bus := pubsub.NewBus()
+	auditLog := log.Sub("audit")
+
 	a := &Session{
-		id:    cfg.SessionID,
-		
-		bus:   pubsub.NewBus(),
-		env:   make(map[string]string),
+		id:  cfg.SessionID,
+		bus: bus,
+		env: make(map[string]string),
 		r: &Agent{
-			history:        cfg.History,
-			runtime:        rt,
-			cwd:            paths.ExpandHome(cfg.CWD),
-			id:             cfg.AgentID,
-			agentName:      cfg.AgentName,
-			agentsDir:      cfg.AgentsDir,
-			promptEnvExtra: cfg.PromptEnvExtra,
-			baseLayers:     cfg.BaseLayers,
-			newDispatcher:  cfg.NewDispatcher,
-			newBackend:     cfg.NewBackend,
+			history:         cfg.History,
+			runtime:         rt,
+			cwd:             paths.ExpandHome(cfg.CWD),
+			id:              cfg.AgentID,
+			agentName:       cfg.AgentName,
+			agentsDir:       cfg.AgentsDir,
+			promptEnvExtra:  cfg.PromptEnvExtra,
+			baseLayers:      cfg.BaseLayers,
+			newDispatcher:   cfg.NewDispatcher,
+			newBackend:      cfg.NewBackend,
+			bus:             bus,
+			log:             log,
+			auditLog:        auditLog,
+			sessionID:       cfg.SessionID,
+			startupMessages: rt.Messages,
+			readPlanStep:    readPlanStep,
 		},
-		log:             log,
-		auditLog:        log.Sub("audit"),
-		sessionsDir:     cfg.SessionsDir,
-		remote:          cfg.Remote,
-		startupMessages: rt.Messages,
-		readPlanStep:    readPlanStep,
-		listHandlers:    cfg.ListHandlers,
+		log:          log,
+		auditLog:     auditLog,
+		sessionsDir:  cfg.SessionsDir,
+		remote:       cfg.Remote,
+		listHandlers: cfg.ListHandlers,
 	}
 	a.r.InitCond()
 	a.r.state = "idle"
@@ -1248,11 +1252,11 @@ func (a *Session) executeTurn(ctx context.Context, input string) string {
 	}
 
 	if a.r.history == nil {
-		for _, msg := range a.startupMessages {
+		for _, msg := range a.r.startupMessages {
 			a.log.Debug("startup: %s", msg)
 			a.emit(infoEvent(msg))
 		}
-		a.startupMessages = nil
+		a.r.startupMessages = nil
 		a.r.history = newHistory(input)
 		if sc := a.spawnContext(ctx); sc != "" {
 			a.r.history.appendUserMessage(sc)
@@ -1279,7 +1283,7 @@ func (a *Session) executeTurn(ctx context.Context, input string) string {
 		ClassifyTier:     a.r.runtime.ClassifyTier,
 		GenerationParams: a.r.runtime.GenParams,
 		MaxSteps:         a.r.runtime.MaxSteps,
-		ReadPlanStep:     a.readPlanStep,
+		ReadPlanStep:     a.r.readPlanStep,
 		TurnError:        a.turnError,
 	}