refactor(add): Create dedicated addFile function

- Move all file reading and content-inlining logic into a new
  'addFile' function in its own 'add.go' file.
- The main function now calls this to parse a log file and then
  appends the returned chats to the main session.
- This improves separation of concerns and makes the main loop cleaner.

add.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"go.wit.com/lib/protobuf/chatpb"
+	"go.wit.com/log"
+)
+
+// addFile reads a protobuf text file, inlines all external content, and returns
+// a self-contained *chatpb.Chats object.
+func addFile(filename string) (*chatpb.Chats, error) {
+	data, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read file %s: %w", filename, err)
+	}
+
+	logData, err := chatpb.UnmarshalChatsTEXT(data)
+	if err != nil {
+		return nil, fmt.Errorf("failed to unmarshal log file %s: %w", filename, err)
+	}
+
+	log.Infof("Successfully parsed log file: %s", filename)
+
+	// Get the directory of the log file to resolve relative content paths.
+	logDir := filepath.Dir(filename)
+
+	// Iterate through the structure to inline all external content.
+	for _, chat := range logData.GetChats() {
+		for _, entry := range chat.GetEntries() {
+			// Inline main content from ContentFile
+			if contentFile := entry.GetContentFile(); contentFile != "" {
+				contentPath := filepath.Join(logDir, contentFile)
+				contentBytes, err := os.ReadFile(contentPath)
+				if err != nil {
+					entry.Content = fmt.Sprintf("--- ERROR: Could not read content file %s: %v ---", contentPath, err)
+				} else {
+					entry.Content = string(contentBytes)
+				}
+			}
+
+			// Inline snippet content from snippet files
+			if snippets := entry.GetSnippets(); snippets != nil {
+				for _, snippet := range snippets {
+					if snippetFile := snippet.GetFilename(); snippetFile != "" {
+						snippetPath := filepath.Join(logDir, snippetFile)
+						contentBytes, err := os.ReadFile(snippetPath)
+						if err != nil {
+							snippet.Content = fmt.Sprintf("--- ERROR: Could not read snippet file %s: %v ---", snippetPath, err)
+						} else {
+							snippet.Content = string(contentBytes)
+						}
+					}
+				}
+			}
+		}
+	}
+
+	log.Info("Successfully inlined all external content.")
+	return logData, nil
+}

main.go

@@ -54,19 +54,19 @@ func main() {
 	}
 
 	if argv.Add != "" {
-		me.chats.AddFile(argv.Add)
-
-		// --- Start Diagnostic Check ---
-		// This loop will check for nil entries in the slice before marshaling.
-		for i, chat := range me.chats.GetChats() {
-			if chat == nil {
-				log.Fatalf("Found a nil *Chat pointer at index %d before calling ConfigSave(). This is the cause of the panic.", i)
+		newChats, err := addFile(argv.Add)
+		if err != nil {
+			badExit(err)
 		}
+		for _, newChat := range newChats.GetChats() {
+			me.chats.AppendByUuid(newChat)
 		}
-		log.Info("Sanity check passed: No nil entries found in the Chats slice.")
-		// --- End Diagnostic Check ---
 
+		// The verifyUuids function should be run on the main chats object
+		// after adding the new chats.
+		if verifyUuids(me.chats) {
 			me.chats.ConfigSave()
+		}
 		okExit("")
 	}