Add website favicon support

http_handler.py

@@ -27,6 +27,7 @@ from app_support import (
     CLIENT_DISCONNECT_ERRORS,
     MAX_JSON_BODY_BYTES,
     MODE_CHOICES,
+    PROJECT_ROOT,
     VERSION,
     client_address_is_local,
     configured_remote_path_roots,
@@ -46,6 +47,8 @@ from app_support import (
     validate_discord_webhook_url,
 )
 
+FAVICON_PATH = PROJECT_ROOT / "favicon.png"
+
 @dataclass(frozen=True)
 class HandlerContext:
     add_to_watchlist: object
@@ -382,6 +385,7 @@ class Handler(BaseHTTPRequestHandler):
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <title>{APP_NAME} sign in</title>
+  <link rel="icon" type="image/png" sizes="32x32" href="/favicon.png">
   <style>
     :root {{
       color-scheme: dark;
@@ -545,6 +549,11 @@ class Handler(BaseHTTPRequestHandler):
             self.ensure_client_access()
             if parsed.path == "/":
                 self.html(Handler._context(self).index_html)
+            elif parsed.path in {"/favicon.png", "/favicon.ico"}:
+                if not FAVICON_PATH.exists():
+                    self.error(HTTPStatus.NOT_FOUND, "Favicon not found")
+                    return
+                self.file(FAVICON_PATH)
             elif parsed.path == "/queue":
                 self.html(Handler._context(self).queue_html)
             elif parsed.path == "/config":