server: fix event subscription context - use connection ctx not request ctx

The subscription was being cancelled after the first read completed
because we used the per-request context. Now using the connection
context so the subscription lives until the fid is clunked or
connection closed.

cmd/olliesrv/internal/session/session_test.go

@@ -1,8 +1,11 @@
 package session
 
 import (
+	"context"
+	"fmt"
 	"os"
 	"testing"
+	"time"
 )
 
 func TestSetCwd_ExpandsTilde(t *testing.T) {
@@ -41,3 +44,77 @@ func TestSetCwd_AbsolutePathUnchanged(t *testing.T) {
 		t.Errorf("SetCwd(/usr/local/bin): got %q, want %q", got, want)
 	}
 }
+
+func TestEventSubscription(t *testing.T) {
+    ctx, cancel := context.WithCancel(context.Background())
+    defer cancel()
+    
+    ch := SubscribeEvents(ctx, "*")
+    
+    // Give subscription time to register
+    time.Sleep(10 * time.Millisecond)
+    
+    // Publish events
+    for i := 0; i < 5; i++ {
+        PublishEvent(fmt.Sprintf("test.event.%d", i), fmt.Sprintf("payload%d", i))
+    }
+    
+    // Collect events
+    timeout := time.After(1 * time.Second)
+    var received []Event
+    for {
+        select {
+        case ev := <-ch:
+            received = append(received, ev)
+            if len(received) >= 5 {
+                goto done
+            }
+        case <-timeout:
+            goto done
+        }
+    }
+done:
+    if len(received) < 5 {
+        t.Errorf("Expected 5 events, got %d", len(received))
+        for i, ev := range received {
+            t.Logf("  [%d] topic=%s payload=%s", i, ev.Topic, ev.Payload)
+        }
+    }
+}
+
+func TestEventSubscriptionFiltered(t *testing.T) {
+    ctx, cancel := context.WithCancel(context.Background())
+    defer cancel()
+    
+    ch := SubscribeEventsFiltered(ctx, "*")
+    
+    // Give subscription time to register
+    time.Sleep(10 * time.Millisecond)
+    
+    // Publish events
+    for i := 0; i < 5; i++ {
+        PublishEvent(fmt.Sprintf("test.event.%d", i), fmt.Sprintf("payload%d", i))
+    }
+    
+    // Collect events
+    timeout := time.After(1 * time.Second)
+    var received []Event
+    for {
+        select {
+        case ev := <-ch:
+            received = append(received, ev)
+            if len(received) >= 5 {
+                goto done
+            }
+        case <-timeout:
+            goto done
+        }
+    }
+done:
+    if len(received) < 5 {
+        t.Errorf("Expected 5 events, got %d", len(received))
+        for i, ev := range received {
+            t.Logf("  [%d] topic=%s payload=%s", i, ev.Topic, ev.Payload)
+        }
+    }
+}

cmd/olliesrv/server.go

@@ -602,6 +602,7 @@ func read(root *fs.Tree, cs *connState, fc *plan9.Fcall, ctx context.Context) *p
 		if path == "event" {
 			cs.mu.RLock()
 			f, fidOK := cs.fids[fc.Fid]
+			connCtx := cs.ctx // Use connection context, not request context
 			cs.mu.RUnlock()
 			if fidOK {
 				f.mu.Lock()
@@ -614,7 +615,7 @@ func read(root *fs.Tree, cs *connState, fc *plan9.Fcall, ctx context.Context) *p
 					if filter == "" {
 						filter = "*"
 					}
-					subCtx, cancel := context.WithCancel(ctx)
+					subCtx, cancel := context.WithCancel(connCtx)
 					ch := session.SubscribeEventsFiltered(subCtx, filter)
 					f.mu.Lock()
 					f.eventFilter = filter