🤖 refactor: Integrate init hooks into DisplayedMessage pattern and centralize bash execution

- Added workspace-init DisplayedMessage type with status tracking
- Extended StreamingMessageAggregator to convert init events to DisplayedMessage
- Created InitMessage component to render init banners in message stream
- Removed local init state management from AIView (eliminated parallel infrastructure)
- Removed legacy WorkspaceMetaEvent type (no longer used)

- Created BashExecutionService to centralize all bash execution
- Provides single abstraction point for future host migration (containers, remote, etc.)
- Eliminates duplicate environment setup across init hooks and bash tool
- executeStreaming() mode for line-by-line output (init hooks)
- Updated IpcMain to use BashExecutionService for init hook execution

Benefits:
- Init events flow through same path as other workspace events
- Centralized state management (no local component state)
- Single source of truth for bash environment setup
- Easier to abstract workspace hosts in future

Tests:
- Added unit tests for aggregator init handling (2 tests)
- All integration tests passing (3/3 init hook tests)
- Typecheck passing for both renderer and main processes

Author: ammar-agent

src/components/AIView.tsx

@@ -29,8 +29,6 @@ import { useGitStatus } from "@/stores/GitStatusStore";
 import { TooltipWrapper, Tooltip } from "./Tooltip";
 import type { DisplayedMessage } from "@/types/message";
 import { useAIViewKeybinds } from "@/hooks/useAIViewKeybinds";
-import type { WorkspaceChatMessage } from "@/types/ipc";
-import { isInitStart, isInitOutput, isInitEnd } from "@/types/ipc";
 
 const ViewContainer = styled.div`
   flex: 1;
@@ -61,37 +59,6 @@ const ViewHeader = styled.div`
   align-items: center;
 `;
 
-// Inline banner that streams workspace init hook output without blocking usage
-const InitHookBanner = styled.div<{ error?: boolean }>`
-  background: ${(p) => (p.error ? "#3a1e1e" : "#1e2a3a")};
-  border-bottom: 1px solid ${(p) => (p.error ? "#653737" : "#2f3f52")};
-  color: #ddd;
-  font-family: var(--font-monospace);
-  font-size: 12px;
-  padding: 8px 12px;
-  display: flex;
-  flex-direction: column;
-  gap: 6px;
-`;
-
-const InitHookHeader = styled.div`
-  display: flex;
-  align-items: center;
-  gap: 8px;
-  color: #ccc;
-`;
-
-const InitHookLog = styled.pre`
-  margin: 0;
-  max-height: 120px;
-  overflow: auto;
-  white-space: pre-wrap;
-  background: rgba(0, 0, 0, 0.15);
-  padding: 6px 8px;
-  border: 1px solid rgba(255, 255, 255, 0.08);
-  border-radius: 4px;
-`;
-
 const WorkspaceTitle = styled.div`
   font-weight: 600;
   color: #cccccc;
@@ -271,37 +238,6 @@ const AIViewInner: React.FC<AIViewProps> = ({
   // Get git status for this workspace
   const gitStatus = useGitStatus(workspaceId);
 
-  // Workspace init hook streaming state
-  const [initLines, setInitLines] = useState<string[]>([]);
-  const [initExitCode, setInitExitCode] = useState<number | null>(null);
-  const [showInit, setShowInit] = useState<boolean>(false);
-
-  // Subscribe to init hook events from chat stream
-  useEffect(() => {
-    const handleMessage = (msg: WorkspaceChatMessage) => {
-      if (isInitStart(msg)) {
-        setShowInit(true);
-        setInitLines([]);
-        setInitExitCode(null);
-      } else if (isInitOutput(msg)) {
-        setShowInit(true);
-        const line = msg.isError ? `ERROR: ${msg.line}` : msg.line;
-        setInitLines((prev) => [...prev, line.trimEnd()]);
-      } else if (isInitEnd(msg)) {
-        const code = msg.exitCode;
-        setInitExitCode(code);
-        if (code === 0) {
-          setTimeout(() => setShowInit(false), 800);
-        } else {
-          setShowInit(true);
-        }
-      }
-    };
-
-    const unsubscribe = window.api.workspace.onChat(workspaceId, handleMessage);
-    return unsubscribe;
-  }, [workspaceId]);
-
   const [editingMessage, setEditingMessage] = useState<{ id: string; content: string } | undefined>(
     undefined
   );
@@ -458,8 +394,10 @@ const AIViewInner: React.FC<AIViewProps> = ({
 
     const mergedMessages = mergeConsecutiveStreamErrors(workspaceState.messages);
     const editCutoffHistoryId = mergedMessages.find(
-      (msg): msg is Exclude<DisplayedMessage, { type: "history-hidden" }> =>
-        msg.type !== "history-hidden" && msg.historyId === editingMessage.id
+      (msg): msg is Exclude<DisplayedMessage, { type: "history-hidden" | "workspace-init" }> =>
+        msg.type !== "history-hidden" &&
+        msg.type !== "workspace-init" &&
+        msg.historyId === editingMessage.id
     )?.historyId;
 
     if (!editCutoffHistoryId) {
@@ -499,8 +437,10 @@ const AIViewInner: React.FC<AIViewProps> = ({
   // When editing, find the cutoff point
   const editCutoffHistoryId = editingMessage
     ? mergedMessages.find(
-        (msg): msg is Exclude<DisplayedMessage, { type: "history-hidden" }> =>
-          msg.type !== "history-hidden" && msg.historyId === editingMessage.id
+        (msg): msg is Exclude<DisplayedMessage, { type: "history-hidden" | "workspace-init" }> =>
+          msg.type !== "history-hidden" &&
+          msg.type !== "workspace-init" &&
+          msg.historyId === editingMessage.id
       )?.historyId
     : undefined;
 
@@ -528,28 +468,6 @@ const AIViewInner: React.FC<AIViewProps> = ({
   return (
     <ViewContainer className={className}>
       <ChatArea ref={chatAreaRef}>
-        {showInit && (
-          <InitHookBanner
-            error={initExitCode !== null && initExitCode !== 0}
-            role="status"
-            aria-live="polite"
-          >
-            <InitHookHeader>
-              {initExitCode === null ? (
-                <span>Running project init hook (.cmux/init)…</span>
-              ) : initExitCode === 0 ? (
-                <span>Init hook completed successfully.</span>
-              ) : (
-                <span>
-                  Init hook exited with code {initExitCode}. Workspace is ready, but some setup
-                  may have failed.
-                </span>
-              )}
-            </InitHookHeader>
-            {initLines.length > 0 && <InitHookLog>{initLines.join("\n")}</InitHookLog>}
-          </InitHookBanner>
-        )}
-
         <ViewHeader>
           <WorkspaceTitle>
             <StatusIndicator
@@ -603,12 +521,17 @@ const AIViewInner: React.FC<AIViewProps> = ({
                   const isAtCutoff =
                     editCutoffHistoryId !== undefined &&
                     msg.type !== "history-hidden" &&
+                    msg.type !== "workspace-init" &&
                     msg.historyId === editCutoffHistoryId;
 
                   return (
                     <React.Fragment key={msg.id}>
                       <div
-                        data-message-id={msg.type !== "history-hidden" ? msg.historyId : undefined}
+                        data-message-id={
+                          msg.type !== "history-hidden" && msg.type !== "workspace-init"
+                            ? msg.historyId
+                            : undefined
+                        }
                       >
                         <MessageRenderer
                           message={msg}

src/components/Messages/InitMessage.tsx

@@ -0,0 +1,63 @@
+import React from "react";
+import styled from "@emotion/styled";
+import type { DisplayedMessage } from "@/types/message";
+
+interface InitMessageProps {
+  message: Extract<DisplayedMessage, { type: "workspace-init" }>;
+  className?: string;
+}
+
+const InitHookBanner = styled.div<{ error?: boolean }>`
+  background: ${(p) => (p.error ? "#3a1e1e" : "#1e2a3a")};
+  border-bottom: 1px solid ${(p) => (p.error ? "#653737" : "#2f3f52")};
+  color: #ddd;
+  font-family: var(--font-monospace);
+  font-size: 12px;
+  padding: 8px 12px;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+`;
+
+const InitHookHeader = styled.div`
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  color: #ccc;
+`;
+
+const InitHookLog = styled.pre`
+  margin: 0;
+  max-height: 120px;
+  overflow: auto;
+  white-space: pre-wrap;
+  background: rgba(0, 0, 0, 0.15);
+  padding: 6px 8px;
+  border: 1px solid rgba(255, 255, 255, 0.08);
+  border-radius: 4px;
+`;
+
+export const InitMessage = React.memo<InitMessageProps>(({ message, className }) => {
+  const isError = message.status === "error";
+
+  return (
+    <InitHookBanner error={isError} className={className}>
+      <InitHookHeader>
+        <span>🔧</span>
+        {message.status === "running" ? (
+          <span>Running init hook...</span>
+        ) : message.status === "success" ? (
+          <span>✅ Init hook completed successfully</span>
+        ) : (
+          <span>
+            Init hook exited with code {message.exitCode}. Workspace is ready, but some setup
+            failed.
+          </span>
+        )}
+      </InitHookHeader>
+      {message.lines.length > 0 && <InitHookLog>{message.lines.join("\n")}</InitHookLog>}
+    </InitHookBanner>
+  );
+});
+
+InitMessage.displayName = "InitMessage";

src/components/Messages/MessageRenderer.tsx

@@ -6,6 +6,7 @@ import { ToolMessage } from "./ToolMessage";
 import { ReasoningMessage } from "./ReasoningMessage";
 import { StreamErrorMessage } from "./StreamErrorMessage";
 import { HistoryHiddenMessage } from "./HistoryHiddenMessage";
+import { InitMessage } from "./InitMessage";
 
 interface MessageRendererProps {
   message: DisplayedMessage;
@@ -46,6 +47,8 @@ export const MessageRenderer = React.memo<MessageRendererProps>(
         return <StreamErrorMessage message={message} className={className} />;
       case "history-hidden":
         return <HistoryHiddenMessage message={message} className={className} />;
+      case "workspace-init":
+        return <InitMessage message={message} className={className} />;
       default:
         console.error("don't know how to render message", message);
         return null;