fix(web): reset live metrics between connections

packages/client/runtime/src/client/index.ts

@@ -143,6 +143,7 @@ export function apply(ctx: Context): void {
       workspaces.handleConnected()
       ctx.emit('connection/reset')
     },
+    onDisconnected: () => { sessions.handleReconnecting() },
   })
   ctx.effect(() => () => { loop.stop() }, 'runtime: connection stream loop')
 }

packages/client/runtime/src/client/sessions/manager.ts

@@ -430,6 +430,12 @@ export class SessionManager {
     for (const session of this.sessions.values()) void session.resync()
   }
 
+  /** Before a replacement stream generation, discard values the Host does not replay. */
+  handleReconnecting(): void {
+    this.modelRequestContextWindows.clear()
+    for (const session of this.sessions.values()) session.handleReconnecting()
+  }
+
   private buildListSnapshot(): SessionListSnapshot {
     const merged: TitledSessionSummary[] = this.summaries.map((summary) => {
       // List rows read the generic 'title' projection key (host-computed unit

packages/client/runtime/src/client/sessions/service.ts

@@ -393,6 +393,11 @@ export class SessionsService {
     this.manager.handleConnected()
   }
 
+  /** Clear connection-local Session state before the next stream generation starts. */
+  handleReconnecting(): void {
+    this.manager.handleReconnecting()
+  }
+
   /**
    * Create a session on the host. Resolution guarantee: by the time the
    * promise resolves, the created session is in the list store and

packages/client/runtime/src/client/sessions/session.ts

@@ -481,6 +481,14 @@ export class Session implements ObservableSnapshot<ConversationSnapshot> {
     this.notifier.markDirty()
   }
 
+  /** Connection-loss boundary: clear values that are not replayed before the next stream starts. */
+  handleReconnecting(): void {
+    if (this.metrics === null && this.contextWindow === undefined) return
+    this.metrics = null
+    this.contextWindow = undefined
+    this.notifier.markDirty()
+  }
+
   /** host/session-removed relay: flag the resident snapshot and clear connection-local capacity. */
   handleRemoved(): void {
     const changed = !this.removed || this.contextWindow !== undefined