feed: BlockOnce with base init, ConsumeFeed via lib9p client

- BlockOnce handler initializes base to current hash on fresh open,
  then blocks until hash changes. Same pattern as statewait.
- ConsumeFeed is a plain function: dials 9P, reads feed in a loop
  (open → block → data → close → repeat), submits to agent.
- Context cancellation closes the 9P client, unblocking Read().
- Called as go ConsumeFeed(ctx, ag) from AddAgent and session resume.

cmd/olliesrv/internal/agent/agent.go

@@ -11,6 +11,7 @@ import (
 	"syscall"
 
 	"ollie/cmd/olliesrv/internal/backend"
+	lib9p "ollie/lib9p/client"
 	olog "ollie/log"
 	"ollie/paths"
 	"ollie/toolsrv"
@@ -680,25 +681,31 @@ func (ag *Agent) FeedWrite(data []byte) {
 	ag.notifyChange()
 }
 
-// StartFeedConsumer spawns a goroutine that blocks on feed changes and
-// submits new data as prompts. Exits when ctx is cancelled.
-func (ag *Agent) StartFeedConsumer(ctx context.Context) {
+// ConsumeFeed reads from the agent's feed file in a loop via 9P.
+// Blocks until feed changes, submits the new data as a prompt.
+// Exits when ctx is cancelled or on read error.
+func ConsumeFeed(ctx context.Context, ag *Agent) {
+	path := fmt.Sprintf("session/%s/agent/%s/feed", ag.sessionID, ag.id)
+	client, err := lib9p.DialDefault()
+	if err != nil {
+		ag.log.Error("feed consumer: dial: %v", err)
+		return
+	}
 	go func() {
-		var base string
-		for {
-			_, ok := ag.WaitChange(ctx, WatchFeed, base)
-			if !ok {
-				return
-			}
-			data := ag.Feed.Get()
-			base = ag.Feed.Hash()
-			if len(data) == 0 {
-				continue
-			}
-			ag.Submit(ctx, string(data))
-			ag.EnsureTrailingNewline()
-		}
+		<-ctx.Done()
+		client.Close()
 	}()
+	for ctx.Err() == nil {
+		data, err := client.Read(path)
+		if err != nil {
+			return
+		}
+		if len(data) == 0 {
+			continue
+		}
+		ag.Submit(ctx, string(data))
+		ag.EnsureTrailingNewline()
+	}
 }
 
 

cmd/olliesrv/internal/fs/spec.go

@@ -408,11 +408,16 @@ func buildAgentChildren(a *agent.Agent, s *session.Session) []virtfs.FsNodeDecl
 			virtfs.BlockOnce(func(cctx context.Context, base string) ([]byte, string, error) {
 				merged, cancel := mergeCtx(s.Ctx, cctx)
 				defer cancel()
+				if base == "" {
+					base = a.Feed.Hash()
+				}
 				_, ok := a.WaitChange(merged, agent.WatchFeed, base)
 				if !ok {
 					return nil, base, merged.Err()
 				}
-				return a.Feed.Get(), a.Feed.Hash(), nil
+				data := a.Feed.Get()
+				hash := a.Feed.Hash()
+				return data, hash, nil
 			}),
 		),
 		virtfs.FileNode("chat", 0444,

cmd/olliesrv/internal/session/session.go

@@ -179,7 +179,7 @@ func (s *Session) Agents() []*agent.Agent { return s.agents }
 func (s *Session) AddAgent(ag *agent.Agent) {
 	s.agents = append(s.agents, ag)
 	if s.Ctx != nil {
-		ag.StartFeedConsumer(s.Ctx)
+		go agent.ConsumeFeed(s.Ctx, ag)
 	}
 }
 
@@ -336,7 +336,7 @@ func (s *Session) Resume() error {
 	s.paused = false
 	// Start feed consumers for restored agents (context now available).
 	for _, ag := range s.agents {
-		ag.StartFeedConsumer(ctx)
+		go agent.ConsumeFeed(ctx, ag)
 	}
 	go s.saveSession()
 	PublishEvent("session."+s.ID+".resume", "")