Improve multiline input handling - support paste, bracket detection, empty line finish

coder

@@ -1092,14 +1092,59 @@ def run_interactive_shell(client: CoderClient, session_manager: SessionManager)
             lines = []
             
             while True:
-                line = input(prompt)
-                # Check if line ends with backslash for continuation
+                try:
+                    line = input(prompt)
+                except EOFError:
+                    # Handle Ctrl+D as end of multiline input
+                    if lines:
+                        break
+                    raise
+                
+                lines.append(line)
+                
+                # Check for explicit continuation with backslash
                 if line.rstrip().endswith('\\'):
-                    lines.append(line.rstrip()[:-1])  # Remove backslash
+                    lines[-1] = line.rstrip()[:-1]  # Remove backslash
                     prompt = f"{Colors.BLUE}  ...>{Colors.RESET} "  # Continuation prompt
-                else:
-                    lines.append(line)
+                    continue
+                
+                # Check for incomplete brackets (multiline paste detection)
+                joined = '\n'.join(lines)
+                open_brackets = joined.count('(') - joined.count(')')
+                open_brackets += joined.count('[') - joined.count(']')
+                open_brackets += joined.count('{') - joined.count('}')
+                
+                # Check for incomplete code blocks or sentences
+                stripped = line.strip()
+                ends_with_colon = stripped.endswith(':')
+                ends_with_open = stripped.endswith(('(', '[', '{'))
+                
+                if open_brackets > 0 or ends_with_colon or ends_with_open:
+                    prompt = f"{Colors.BLUE}  ...>{Colors.RESET} "  # Continuation prompt
+                    continue
+                
+                # Empty line after content - finish input (for paste mode)
+                if not stripped and len(lines) > 1:
+                    lines.pop()  # Remove the empty line
                     break
+                
+                # Single line input - we're done
+                if len(lines) == 1 and not open_brackets and not ends_with_colon and not ends_with_open:
+                    break
+                
+                # Multiple lines with balanced brackets - finish on empty line or new prompt
+                if open_brackets == 0 and not ends_with_colon and not ends_with_open:
+                    # For pasted multiline content, finish immediately
+                    # For manual entry, require empty line
+                    if '\n'.join(lines).count('\n') >= 1 and not stripped:
+                        lines.pop()  # Remove the empty line
+                        break
+                    elif '\n'.join(lines).count('\n') >= 1 and stripped:
+                        # Pasted content with balanced brackets - likely done
+                        break
+                    else:
+                        prompt = f"{Colors.BLUE}  ...>{Colors.RESET} "
+                        continue
             
             user_input = '\n'.join(lines).strip()
             
@@ -1237,7 +1282,10 @@ def print_help():
   {Colors.YELLOW}/confirm <tool> <y/n>{Colors.RESET}  Enable/disable tool confirmation
 
 {Colors.BOLD}{Colors.CYAN}Multiline Input:{Colors.RESET}
-  End a line with {Colors.YELLOW}\\{Colors.RESET} to continue on next line
+  - End a line with {Colors.YELLOW}\\{Colors.RESET} to continue
+  - Or paste multiline content directly
+  - Or press Enter twice to finish
+  - Unclosed brackets ( ) [ ] {{ }} or : continue automatically
   Example:
     CoderCLI> This is a \\
       ...> multiline message