fix(prometheus): a refused token stops the scraping, as Home Assistant bans an address after a few refusals (#6355)

Also names the Home Assistant connection by its address in the audit log and
timeline, where its id showed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/prometheus/scraper.py

@@ -18,6 +18,11 @@ class ScrapeError(Exception):
     """Why a scrape got nothing, said to the person."""
 
 
+class TokenRefused(ScrapeError):
+    """The endpoint refused the token. Asking again won't change that, and
+    Home Assistant, for one, bans an address after a few refusals."""
+
+
 async def scrape(url: str, token: str = "", verify_tls: bool = True,
                  transport: httpx.AsyncBaseTransport | None = None) -> dict[str, prometheus.Family]:
     """The endpoint's families. `transport` stands in for the network in tests."""
@@ -29,8 +34,8 @@ async def scrape(url: str, token: str = "", verify_tls: bool = True,
                                      transport=transport, follow_redirects=False) as client:
             async with client.stream("GET", url, headers=headers) as response:
                 if response.status_code in (401, 403):
-                    raise ScrapeError(f"Answered {response.status_code}: the token was refused. "
-                                      "Check the token, or make a new one on the service.")
+                    raise TokenRefused(f"Answered {response.status_code}: the token was refused. "
+                                       "Check the token, or make a new one on the service.")
                 if response.status_code != 200:
                     raise ScrapeError(f"Answered {response.status_code} {response.reason_phrase}, not metrics.")
                 body = bytearray()