feat: add heartbeat visibility filtering for webchat

- Add isHeartbeat to AgentRunContext to track heartbeat runs
- Pass isHeartbeat flag through agent runner execution
- Suppress webchat broadcast (deltas + final) for heartbeat runs when showOk is false
- Webchat uses channels.defaults.heartbeat settings (no per-channel config)
- Default behavior: hide HEARTBEAT_OK from webchat (matches other channels)

This allows users to control whether heartbeat responses appear in
the webchat UI via channels.defaults.heartbeat.showOk (defaults to false).

src/infra/agent-events.ts

@@ -14,6 +14,7 @@ export type AgentEventPayload = {
 export type AgentRunContext = {
   sessionKey?: string;
   verboseLevel?: VerboseLevel;
+  isHeartbeat?: boolean;
 };
 
 // Keep per-run counters so streams stay strictly monotonic per runId.
@@ -34,6 +35,9 @@ export function registerAgentRunContext(runId: string, context: AgentRunContext)
   if (context.verboseLevel && existing.verboseLevel !== context.verboseLevel) {
     existing.verboseLevel = context.verboseLevel;
   }
+  if (context.isHeartbeat !== undefined && existing.isHeartbeat !== context.isHeartbeat) {
+    existing.isHeartbeat = context.isHeartbeat;
+  }
 }
 
 export function getAgentRunContext(runId: string) {

src/infra/heartbeat-visibility.test.ts

@@ -247,4 +247,58 @@ describe("resolveHeartbeatVisibility", () => {
       useIndicator: true,
     });
   });
+
+  it("webchat uses channel defaults only (no per-channel config)", () => {
+    const cfg = {
+      channels: {
+        defaults: {
+          heartbeat: {
+            showOk: true,
+            showAlerts: false,
+            useIndicator: false,
+          },
+        },
+      },
+    } as ClawdbotConfig;
+
+    const result = resolveHeartbeatVisibility({ cfg, channel: "webchat" });
+
+    expect(result).toEqual({
+      showOk: true,
+      showAlerts: false,
+      useIndicator: false,
+    });
+  });
+
+  it("webchat returns defaults when no channel defaults configured", () => {
+    const cfg = {} as ClawdbotConfig;
+
+    const result = resolveHeartbeatVisibility({ cfg, channel: "webchat" });
+
+    expect(result).toEqual({
+      showOk: false,
+      showAlerts: true,
+      useIndicator: true,
+    });
+  });
+
+  it("webchat ignores accountId (only uses defaults)", () => {
+    const cfg = {
+      channels: {
+        defaults: {
+          heartbeat: {
+            showOk: true,
+          },
+        },
+      },
+    } as ClawdbotConfig;
+
+    const result = resolveHeartbeatVisibility({
+      cfg,
+      channel: "webchat",
+      accountId: "some-account",
+    });
+
+    expect(result.showOk).toBe(true);
+  });
 });

src/infra/heartbeat-visibility.ts

@@ -1,6 +1,6 @@
 import type { ClawdbotConfig } from "../config/config.js";
 import type { ChannelHeartbeatVisibilityConfig } from "../config/types.channels.js";
-import type { DeliverableMessageChannel } from "../utils/message-channel.js";
+import type { DeliverableMessageChannel, GatewayMessageChannel } from "../utils/message-channel.js";
 
 export type ResolvedHeartbeatVisibility = {
   showOk: boolean;
@@ -14,13 +14,28 @@ const DEFAULT_VISIBILITY: ResolvedHeartbeatVisibility = {
   useIndicator: true, // Emit indicator events
 };
 
+/**
+ * Resolve heartbeat visibility settings for a channel.
+ * Supports both deliverable channels (telegram, signal, etc.) and webchat.
+ * For webchat, uses channels.defaults.heartbeat since webchat doesn't have per-channel config.
+ */
 export function resolveHeartbeatVisibility(params: {
   cfg: ClawdbotConfig;
-  channel: DeliverableMessageChannel;
+  channel: GatewayMessageChannel;
   accountId?: string;
 }): ResolvedHeartbeatVisibility {
   const { cfg, channel, accountId } = params;
 
+  // Webchat uses channel defaults only (no per-channel or per-account config)
+  if (channel === "webchat") {
+    const channelDefaults = cfg.channels?.defaults?.heartbeat;
+    return {
+      showOk: channelDefaults?.showOk ?? DEFAULT_VISIBILITY.showOk,
+      showAlerts: channelDefaults?.showAlerts ?? DEFAULT_VISIBILITY.showAlerts,
+      useIndicator: channelDefaults?.useIndicator ?? DEFAULT_VISIBILITY.useIndicator,
+    };
+  }
+
   // Layer 1: Global channel defaults
   const channelDefaults = cfg.channels?.defaults?.heartbeat;