feat: implement terminal messenger with conversation management

feat: implement terminal messenger with conversation management

- Add terminal-based messenger client connecting to Verint API endpoint
- Implement colorized output (blue for user input, green for assistant
responses)
- Add readline integration for arrow key navigation through input
history
- Implement conversation persistence with unique history files per
conversation ID
- Add conversation resume feature listing 5 most recent conversations
- Store and auto-load model names per conversation
- Display last 10 message exchanges when resuming conversations
- Log full conversation history (user + assistant messages) with
timestamps
- Simplify codebase by consolidating file operations into reusable
functions
- Fix Sscanf error handling for conversation selection

Features:
- Request/response handling with conversation context via
previous_response_id
- Three file types per conversation: .tmp (readline history), _log.txt
(full conversation), _meta.txt (model name)
- Automatic conversation ID assignment after first message
- Clean exit handling and proper resource cleanup

terminal-messenger/application/README.md

@@ -1,14 +1,16 @@
 # Terminal Messenger
 
-A simple, colorful terminal-based messenger application written in Go that connects to a remote messaging endpoint.
+A simple, colorful terminal-based messenger application written in Go that connects to a remote messaging endpoint with conversation persistence and history management.
 
 ## Features
 
 - 🎨 **Colorized output** - Blue for your input, green for assistant responses
 - ⌨️ **Input history** - Navigate previous messages with arrow keys
-- 💬 **Conversation context** - Maintains conversation continuity across messages
+- 💾 **Conversation persistence** - Resume previous conversations seamlessly
+- 📝 **Full conversation logs** - Both user and assistant messages saved with timestamps
+- 🔄 **Auto-resume** - Lists your 5 most recent conversations on startup
+- 🏷️ **Model tracking** - Automatically saves and loads the model used per conversation
 - 🚀 **Simple and fast** - Minimal setup, quick startup
-- 📝 **Line editing** - Full cursor movement and text editing support
 
 ## Prerequisites
 
@@ -19,26 +21,20 @@ A simple, colorful terminal-based messenger application written in Go that conne
 
 1. **Clone or download the project**
 
-2. **Initialize Go module**
-
-   ```bash
-   go mod init messenger
-   ```
-
-3. **Install dependencies**
+2. **Install dependencies**
 
    ```bash
    go get github.com/chzyer/readline
    ```
 
-4. **Build the application (optional)**
+3. **Build the application (optional)**
    ```bash
    go build -o messenger main.go
    ```
 
 ## Usage
 
-### Running the application
+### Starting the application
 
 **Using go run:**
 
@@ -52,13 +48,29 @@ go run main.go
 ./messenger
 ```
 
-### Getting started
+### First time usage
 
-1. When prompted, enter a model name (or press Enter for "default")
-2. Start typing your messages
-3. The assistant will respond to each message
-4. Use arrow keys to navigate through your input history
-5. Type `quit` or `exit` to end the session
+1. Press 'n' or Enter when asked about continuing a conversation
+2. Enter a model name (or press Enter for "default")
+3. Start chatting with the assistant
+4. Type `quit` or `exit` to end the session
+
+### Resuming a conversation
+
+1. When prompted, you'll see your recent conversations:
+
+   ```
+   Recent conversations:
+   1. resp_d2925cd3-d99c-46f6-a70a-05b1453b8d4f (model: gpt-4)
+   2. resp_a1234567-89ab-cdef-0123-456789abcdef (model: default)
+
+   Continue? (enter number or 'n' for new):
+   ```
+
+2. Enter the number (1-5) to resume that conversation
+3. The last 10 message exchanges will be displayed
+4. The model name is automatically loaded
+5. Continue chatting from where you left off
 
 ### Keyboard shortcuts
 
@@ -67,9 +79,26 @@ go run main.go
 - **←/→ (Left/Right arrows)** - Move cursor within current input
 - **Ctrl+A** - Jump to beginning of line
 - **Ctrl+E** - Jump to end of line
-- **Ctrl+C** - Interrupt/exit application
+- **Ctrl+C** or type `quit`/`exit` - Exit application
 
-## Configuration
+## How It Works
+
+### Conversation Files
+
+For each conversation, three files are created in `/tmp/`:
+
+1. **`messenger_{ID}.tmp`** - Readline history for arrow key navigation (user inputs only)
+2. **`messenger_{ID}_log.txt`** - Full conversation log with timestamps (both user and assistant)
+3. **`messenger_{ID}_meta.txt`** - Stores the model name for the conversation
+
+### Conversation Continuity
+
+- Each response from the API includes a unique `id`
+- This ID is sent as `previous_response_id` in subsequent requests
+- This maintains conversation context across the entire session
+- When resuming, the conversation ID is loaded and context is preserved
+
+## API Configuration
 
 The application connects to:
 
@@ -81,8 +110,6 @@ To change the endpoint, modify the `apiURL` constant in `main.go`.
 
 ### Request format
 
-The application sends POST requests with the following JSON structure:
-
 ```json
 {
   "input": "your message here",
@@ -96,8 +123,6 @@ The application sends POST requests with the following JSON structure:
 
 ### Response format
 
-Expected response structure:
-
 ```json
 {
   "id": "response-id",
@@ -126,7 +151,7 @@ Expected response structure:
 
 ```
 .
-├── main.go              # Main application file
+├── main.go              # Main application file (~160 lines)
 ├── go.mod               # Go module file
 └── README.md            # This file
 ```
@@ -151,7 +176,11 @@ go mod tidy
 
 ### History file permissions
 
-The app creates a history file at `/tmp/messenger_history.tmp`. If you encounter permission errors, ensure you have write access to `/tmp/`.
+The app creates files in `/tmp/`. If you encounter permission errors, ensure you have write access to `/tmp/`.
+
+### Cannot find previous conversations
+
+Conversations are stored in `/tmp/` which may be cleared on system restart. For permanent storage, modify the file paths in `main.go` to use a different directory like `~/.messenger/`.
 
 ## Dependencies