Remove ALL data truncation from compaction process

This commit removes all data truncation that was incorrectly added in
the previous optimization commit, ensuring COMPLETE history preservation
as required by the user.

## Changes

1. **_write_history_to_file**:
   - Removed max_tool_output_size parameter
   - Removed truncation of function arguments
   - Removed truncation of tool outputs
   - Updated docstring to emphasize complete data preservation

2. **_format_history_for_summary**:
   - Removed 500 character limit on tool outputs
   - Removed [-50:] message limit
   - Now returns ALL messages without any truncation
   - Updated docstring to emphasize complete preservation

## Guarantees

✅ NO truncation of any data
✅ NO message limits
✅ NO loss of information
✅ COMPLETE history preservation
✅ Full tool outputs preserved
✅ Full function arguments preserved
✅ All messages included

The file-based streaming approach still prevents memory issues by
writing incrementally to disk, while the batch processing handles
large histories efficiently. The only difference now is that ALL
data is preserved without any truncation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/cai/repl/commands/memory.py

@@ -1415,6 +1415,8 @@ This session is being continued from a previous conversation that ran out of con
 
         NOTE: This method is deprecated and kept for backwards compatibility.
         Use _write_history_to_file for better memory efficiency with large histories.
+
+        IMPORTANT: Preserves COMPLETE history without truncation or message limits.
         """
         formatted_parts = []
 
@@ -1426,7 +1428,7 @@ This session is being continued from a previous conversation that ran out of con
             if not content:
                 continue
 
-            # Format based on role
+            # Format based on role - PRESERVE EVERYTHING
             if role == "user":
                 formatted_parts.append(f"USER: {content}")
             elif role == "assistant":
@@ -1435,27 +1437,28 @@ This session is being continued from a previous conversation that ran out of con
                     tool_info = []
                     for tc in msg["tool_calls"]:
                         if hasattr(tc, "function"):
+                            # PRESERVE FULL ARGUMENTS
                             tool_info.append(f"{tc.function.name}({tc.function.arguments})")
                     if tool_info:
                         formatted_parts.append(f"ASSISTANT (tools): {', '.join(tool_info)}")
                 if content:
                     formatted_parts.append(f"ASSISTANT: {content}")
             elif role == "tool":
-                # Include important tool outputs
-                if len(str(content)) < 500:  # Only include short outputs
-                    formatted_parts.append(f"TOOL OUTPUT: {content}")
-                else:
-                    formatted_parts.append(f"TOOL OUTPUT: [Long output truncated]")
+                # PRESERVE FULL TOOL OUTPUT - no truncation
+                formatted_parts.append(f"TOOL OUTPUT: {content}")
 
-        return "\n\n".join(formatted_parts[-50:])  # Limit to last 50 exchanges
+        # Return ALL messages, no limit
+        return "\n\n".join(formatted_parts)
 
-    def _write_history_to_file(self, history: List[Dict[str, Any]], output_file: Path, max_tool_output_size: int = 1000) -> tuple[int, int]:
+    def _write_history_to_file(self, history: List[Dict[str, Any]], output_file: Path) -> tuple[int, int]:
         """Write message history to file using streaming to avoid memory issues.
 
+        IMPORTANT: This writes the COMPLETE history without any truncation or loss of data.
+        All messages, tool outputs, and function arguments are preserved in full.
+
         Args:
             history: Message history to write
             output_file: Path to output file
-            max_tool_output_size: Maximum size for tool outputs (truncate longer ones)
 
         Returns:
             Tuple of (messages_written, total_size_bytes)
@@ -1472,7 +1475,7 @@ This session is being continued from a previous conversation that ran out of con
                 if not content:
                     continue
 
-                # Format based on role
+                # Format based on role - PRESERVE EVERYTHING
                 message_text = None
                 if role == "user":
                     message_text = f"USER: {content}\n\n"
@@ -1482,10 +1485,8 @@ This session is being continued from a previous conversation that ran out of con
                         tool_info = []
                         for tc in msg["tool_calls"]:
                             if hasattr(tc, "function"):
-                                # Truncate large function arguments
+                                # PRESERVE FULL ARGUMENTS - no truncation
                                 args = str(tc.function.arguments)
-                                if len(args) > max_tool_output_size:
-                                    args = args[:max_tool_output_size] + "... [truncated]"
                                 tool_info.append(f"{tc.function.name}({args})")
                         if tool_info:
                             message_text = f"ASSISTANT (tools): {', '.join(tool_info)}\n\n"
@@ -1495,10 +1496,8 @@ This session is being continued from a previous conversation that ran out of con
                         else:
                             message_text = f"ASSISTANT: {content}\n\n"
                 elif role == "tool":
-                    # Truncate large tool outputs
+                    # PRESERVE FULL TOOL OUTPUT - no truncation
                     content_str = str(content)
-                    if len(content_str) > max_tool_output_size:
-                        content_str = content_str[:max_tool_output_size] + "... [truncated for size]"
                     message_text = f"TOOL OUTPUT: {content_str}\n\n"
 
                 if message_text: