refactor: improve shell performance, fix bugs on the git tab and promote login to a standalone component

Implement PTY session persistence with 30-minute timeout for shell reconnection. Sessions are now keyed by project path and session ID, preserving terminal state across UI disconnections with buffered output replay.
Refactor Shell component to use refs for stable prop access, removing unnecessary isActive prop and improving WebSocket connection lifecycle management. Replace conditional rendering with early returns in MainContent for better performance.
Add directory handling in git operations: support discarding, diffing, and viewing directories in untracked files. Prevent errors when staging or generating commit messages for directories.
Extract LoginModal into reusable component for Claude and Cursor CLI authentication. Add minimal mode to StandaloneShell for embedded use cases. Update Settings to use new LoginModal component.
Improve terminal dimensions handling by passing client-provided cols and rows to PTY spawn. Add comprehensive logging for session lifecycle and API operations.

src/components/StandaloneShell.jsx

@@ -1,14 +1,13 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useCallback } from 'react';
 import Shell from './Shell.jsx';
 
 /**
  * Generic Shell wrapper that can be used in tabs, modals, and other contexts.
  * Provides a flexible API for both standalone and session-based usage.
- * 
+ *
  * @param {Object} project - Project object with name, fullPath/path, displayName
  * @param {Object} session - Session object (optional, for tab usage)
  * @param {string} command - Initial command to run (optional)
- * @param {boolean} isActive - Whether the shell is active (for tab usage, default: true)
  * @param {boolean} isPlainShell - Use plain shell mode vs Claude CLI (default: auto-detect)
  * @param {boolean} autoConnect - Whether to auto-connect when mounted (default: true)
  * @param {function} onComplete - Callback when process completes (receives exitCode)
@@ -17,33 +16,32 @@ import Shell from './Shell.jsx';
  * @param {string} className - Additional CSS classes
  * @param {boolean} showHeader - Whether to show custom header (default: true)
  * @param {boolean} compact - Use compact layout (default: false)
+ * @param {boolean} minimal - Use minimal mode: no header, no overlays, auto-connect (default: false)
  */
 function StandaloneShell({
   project,
   session = null,
   command = null,
-  isActive = true,
-  isPlainShell = null, // Auto-detect: true if command provided, false if session provided
+  isPlainShell = null,
   autoConnect = true,
   onComplete = null,
   onClose = null,
   title = null,
   className = "",
   showHeader = true,
-  compact = false
+  compact = false,
+  minimal = false
 }) {
   const [isCompleted, setIsCompleted] = useState(false);
 
-  // Auto-detect isPlainShell based on props
   const shouldUsePlainShell = isPlainShell !== null ? isPlainShell : (command !== null);
 
-  // Handle process completion
-  const handleProcessComplete = (exitCode) => {
+  const handleProcessComplete = useCallback((exitCode) => {
     setIsCompleted(true);
     if (onComplete) {
       onComplete(exitCode);
     }
-  };
+  }, [onComplete]);
 
   if (!project) {
     return (
@@ -62,9 +60,9 @@ function StandaloneShell({
   }
 
   return (
-    <div className={`h-full flex flex-col ${className}`}>
+    <div className={`h-full w-full flex flex-col ${className}`}>
       {/* Optional custom header */}
-      {showHeader && title && (
+      {!minimal && showHeader && title && (
         <div className="flex-shrink-0 bg-gray-800 border-b border-gray-700 px-4 py-2">
           <div className="flex items-center justify-between">
             <div className="flex items-center space-x-2">
@@ -89,14 +87,15 @@ function StandaloneShell({
       )}
 
       {/* Shell component wrapper */}
-      <div className="flex-1">
+      <div className="flex-1 w-full min-h-0">
         <Shell
           selectedProject={project}
           selectedSession={session}
-          isActive={isActive}
           initialCommand={command}
           isPlainShell={shouldUsePlainShell}
           onProcessComplete={handleProcessComplete}
+          minimal={minimal}
+          autoConnect={minimal ? true : autoConnect}
         />
       </div>
     </div>