fix(composer): reconcile live-activity strip with the dock geometry from #3151

Post-rebase integration fixes after rebasing onto main, which landed the
composer dock geometry contract (PR #3151) in the same region this branch
reworks. The rebase kept main's dock architecture (reserved bottom rail +
ComposerActivityAccessory fade) with the branch's pill strip rendered
inside it; this commit cleans up the fallout:

- ChannelPane.tsx: re-add the useChannelWorkingAgentPubkeys import — the
  dock's reserved-rail toggle (composer-dock--with-activity) still needs
  the channel-level working-set check even though
  ChannelComposerActivityRow computes its own copy — and consolidate the
  gating into a single hasComposerBottomActivity expression
- ChannelComposerActivityAccessory.tsx: delete — main's channel-level
  wrapper from #3151 is fully superseded by ChannelComposerActivityRow
  rendered inside ComposerActivityAccessory
- AppShell.tsx / routes/root.tsx: move the temporary DebugHarnessMount
  from AppShell (999/1000 lines on main, so the mount no longer fits the
  file-size ratchet) to the root route via a RootComponent wrapper
- agents/debug/README.md + DebugHarnessMount.tsx: update the removal
  instructions and header comment for the new mount location

Validated with just desktop-check, 3,817 desktop unit tests, and the
channels / composer-overflow / threadpane-ultrawide e2e specs (88
passing).

Co-authored-by: Taylor Ho <taylorkmho@gmail.com>
Signed-off-by: Taylor Ho <taylorkmho@gmail.com>

desktop/src/features/channels/ui/ChannelComposerActivityAccessory.tsx

@@ -1,69 +1,52 @@
 import type { ComponentProps } from "react";
 
-import { CardMintComposerChip } from "@/features/agents/ui/CardMintComposerChip";
 import { useCardMintJobs } from "@/features/agents/cardMintStore";
-import { BotActivityComposerAction } from "@/features/channels/ui/BotActivityBar";
+import { CardMintComposerChip } from "@/features/agents/ui/CardMintComposerChip";
+import { ChannelComposerActivityRow } from "@/features/channels/ui/ChannelComposerActivityRow";
 import { ComposerActivityAccessory } from "@/features/messages/ui/ComposerActivityAccessory";
-import { TypingIndicatorRow } from "@/features/messages/ui/TypingIndicatorRow";
 
 type ChannelComposerActivityAccessoryProps = {
-  agents: ComponentProps<typeof BotActivityComposerAction>["agents"];
-  channel: ComponentProps<typeof TypingIndicatorRow>["channel"];
-  currentPubkey: ComponentProps<typeof TypingIndicatorRow>["currentPubkey"];
+  agents: ComponentProps<typeof ChannelComposerActivityRow>["agents"];
+  channel: ComponentProps<typeof ChannelComposerActivityRow>["channel"];
+  currentPubkey: ComponentProps<
+    typeof ChannelComposerActivityRow
+  >["currentPubkey"];
   onOpenAgentSession: ComponentProps<
-    typeof BotActivityComposerAction
+    typeof ChannelComposerActivityRow
   >["onOpenAgentSession"];
-  openAgentSessionPubkey: ComponentProps<
-    typeof BotActivityComposerAction
-  >["openAgentSessionPubkey"];
-  profiles: ComponentProps<typeof BotActivityComposerAction>["profiles"];
+  profiles: ComponentProps<typeof ChannelComposerActivityRow>["profiles"];
   typingPubkeys: string[];
   visible: boolean;
-  workingBotPubkeys: string[];
 };
 
+/** Main's shared channel activity host with the unified live-activity strip. */
 export function ChannelComposerActivityAccessory({
   agents,
   channel,
   currentPubkey,
   onOpenAgentSession,
-  openAgentSessionPubkey,
   profiles,
   typingPubkeys,
   visible,
-  workingBotPubkeys,
 }: ChannelComposerActivityAccessoryProps) {
   const cardMintJobs = useCardMintJobs();
+
   return (
     <ComposerActivityAccessory
       className="px-5"
       testId="channel-composer-activity-row"
       visible={visible}
     >
-      <div className="flex w-full items-center gap-2 overflow-visible pl-2">
+      <div className="flex h-8.5 w-full items-center gap-2 overflow-visible pb-1.5 pl-2">
         {cardMintJobs.length > 0 ? <CardMintComposerChip /> : null}
-        {workingBotPubkeys.length > 0 ? (
-          <div className="flex min-w-0 flex-1 overflow-visible">
-            <BotActivityComposerAction
-              agents={agents}
-              channelId={channel?.id ?? null}
-              onOpenAgentSession={onOpenAgentSession}
-              openAgentSessionPubkey={openAgentSessionPubkey}
-              profiles={profiles}
-              workingBotPubkeys={workingBotPubkeys}
-              variant="inline"
-            />
-          </div>
-        ) : null}
-        {typingPubkeys.length > 0 ? (
-          <TypingIndicatorRow
-            channel={channel}
-            className="min-w-0 flex-1 py-0 pl-[calc(0.75rem+1px)] pr-0 sm:pl-[calc(1rem+1px)]"
-            currentPubkey={currentPubkey}
-            profiles={profiles}
-            typingPubkeys={typingPubkeys}
-          />
-        ) : null}
+        <ChannelComposerActivityRow
+          agents={agents}
+          channel={channel}
+          currentPubkey={currentPubkey}
+          onOpenAgentSession={onOpenAgentSession}
+          profiles={profiles}
+          typingPubkeys={typingPubkeys}
+        />
       </div>
     </ComposerActivityAccessory>
   );

desktop/src/features/channels/ui/ChannelComposerActivityRow.tsx

@@ -132,11 +132,7 @@ export function ChannelComposerActivityRow({
   }, [agentTypingPubkeys.length, agents, profiles]);
 
   return (
-    <div
-      className="h-8.5 overflow-visible bg-background px-5 pb-1.5 pt-0"
-      data-testid="channel-composer-activity-row"
-    >
-      <div className="flex h-full w-full items-center overflow-visible">
+    <div className="flex min-w-0 flex-1 items-center overflow-visible">
         {/* One strip hosts both groups: working pills plus the typing group
             as the strip's trailing slot sibling, so they share the scroller,
             edge fades, and layout/enter/exit animations. When the row gets
@@ -165,7 +161,6 @@ export function ChannelComposerActivityRow({
             workingBotPubkeys={pillBotPubkeys}
           />
         ) : null}
-      </div>
     </div>
   );
 }

desktop/src/features/channels/ui/ChannelPane.tsx

@@ -38,8 +38,7 @@ import { useFocusDrawerPresence } from "@/features/channels/ui/useFocusDrawerPre
 import { useChannelWorkingAgentPubkeys } from "@/features/agents/agentWorkingSignal";
 import { useCardMintJobs } from "@/features/agents/cardMintStore";
 import { BotActivityComposerAction } from "@/features/channels/ui/BotActivityBar";
-import { ChannelComposerActivityRow } from "@/features/channels/ui/ChannelComposerActivityRow";
-import { ComposerActivityAccessory } from "@/features/messages/ui/ComposerActivityAccessory";
+import { ChannelComposerActivityAccessory } from "@/features/channels/ui/ChannelComposerActivityAccessory";
 import { TypingIndicatorRow } from "@/features/messages/ui/TypingIndicatorRow";
 import {
   containsWelcomePersonaMention,
@@ -740,16 +739,15 @@ export const ChannelPane = React.memo(function ChannelPane({
                     bottom rail, so fading it cannot change the observed
                     overlay height or move the conversation. Its natural
                     content height remains responsive. */}
-                  <ComposerActivityAccessory visible={hasComposerBottomActivity}>
-                    <ChannelComposerActivityRow
-                      agents={activityAgents}
-                      channel={activeChannel}
-                      currentPubkey={currentPubkey}
-                      onOpenAgentSession={onOpenAgentSession}
-                      profiles={profiles}
-                      typingPubkeys={typingPubkeys}
-                    />
-                  </ComposerActivityAccessory>
+                  <ChannelComposerActivityAccessory
+                    agents={activityAgents}
+                    channel={activeChannel}
+                    currentPubkey={currentPubkey}
+                    onOpenAgentSession={onOpenAgentSession}
+                    profiles={profiles}
+                    typingPubkeys={typingPubkeys}
+                    visible={hasComposerBottomActivity}
+                  />
                 </div>
               </div>
             )}