feat: add SIGTERM handling and update typer dependency (#4548)

* Update `typer` dependency to version 0.13.0 in `pyproject.toml`

* refactor: Simplify exception handling in the CLI

* Enhance lifespan function with clean shutdown and logging improvements

* Add graceful shutdown handling for SIGTERM and SIGINT signals

- Introduce signal handlers to manage SIGTERM and SIGINT for graceful server shutdown.
- Update exception handling to ensure processes terminate properly and log shutdown events.
- Modify server run logic to support signal-based shutdowns, improving reliability.

---------

Co-authored-by: Nadir J <31660040+NadirJ@users.noreply.github.com>

src/backend/base/pyproject.toml

@@ -119,7 +119,7 @@ dependencies = [
     "langchain-experimental>=0.0.61",
     "pydantic>=2.7.0",
     "pydantic-settings>=2.2.0",
-    "typer>=0.12.0",
+    "typer>=0.13.0",
     "cachetools>=5.3.1",
     "platformdirs>=4.2.0",
     "python-multipart>=0.0.12",