feat: SSE support (#162)

* event bus implementation

* update tests

* docs update

* review fixes

* update configs

* fix typo

* frontend changes

* install missing pacakge

* queue processing simplification

pyproject.toml

@@ -58,6 +58,7 @@ web = [
     "aiohttp",
     "aiohttp_cors",
     "aiohttp_jinja2",
+    "aiohttp_sse",
 ]
 web-auth = [
     "ahriman[web]",