Refactor IPC and DTO structures; remove unused code and streamline message handling

- Removed unused structs and methods from `response.rs`, `usage.rs`, and `client.rs`.
- Simplified `Connection` handling in `conn.rs` to only support Unix sockets.
- Updated `IpcServer` to exclusively use Unix sockets and removed TCP handling.
- Cleaned up `editlog.rs` by removing loading and recent entry methods.
- Refactored `memory.rs` to eliminate unused functions related to lesson promotion and retrospective creation.
- Enhanced `search.rs` to support multiple search providers and improved error handling.
- Updated chat view logic to simplify message display and improve user experience.
- Removed deprecated modules and constants from various files to streamline the codebase.

src/resources.rs

@@ -1,16 +1,6 @@
 pub const SYSTEM_PROMPT: &str = include_str!("../src-misc/system-prompt.txt");
 pub const SYSTEM_TOOLS: &str = include_str!("../src-misc/system-tools.txt");
 
-pub const BANNER: &str = r"
-███████╗███████╗███████╗██████╗ ███████╗██╗  ██╗
-╚══███╔╝██╔════╝██╔════╝██╔══██╗██╔════╝╚██╗██╔╝
-  ███╔╝ █████╗  ███████╗██║  ██║█████╗   ╚███╔╝
- ███╔╝  ██╔══╝  ╚════██║██║  ██║██╔══╝   ██╔██╗
-███████╗███████╗███████║██████╔╝███████╗██╔╝ ██╗
-╚══════╝╚══════╝╚══════╝╚═════╝ ╚══════╝╚═╝  ╚═╝
-          Autonomous Agentic Shell
-";
-
 pub const HELP_TEXT: &str = "
 ZESDEX - Help
 =============
@@ -46,4 +36,4 @@ Commands:
   Any text is sent to the AI assistant as a prompt.
   File paths use workspace-relative notation.
   Use [0]/path for multi-workspace setups.
-";
+ ";