Webmention improvements

- Tweak design for IndieAuth login flow
 - Webmentions notifications support
 - Refactor webmentions processing

app/utils/microformats.py

@@ -7,19 +7,28 @@ from loguru import logger
 from app import config
 
 
-async def fetch_and_parse(url: str) -> tuple[dict[str, Any], str] | None:
+class URLNotFoundOrGone(Exception):
+    pass
+
+
+async def fetch_and_parse(url: str) -> tuple[dict[str, Any], str]:
     async with httpx.AsyncClient() as client:
+        resp = await client.get(
+            url,
+            headers={
+                "User-Agent": config.USER_AGENT,
+            },
+            follow_redirects=True,
+        )
+        if resp.status_code in [404, 410]:
+            raise URLNotFoundOrGone
+
         try:
-            resp = await client.get(
-                url,
-                headers={
-                    "User-Agent": config.USER_AGENT,
-                },
-                follow_redirects=True,
-            )
             resp.raise_for_status()
-        except (httpx.HTTPError, httpx.HTTPStatusError):
-            logger.exception(f"Failed to discover webmention endpoint for {url}")
-            return None
+        except httpx.HTTPStatusError:
+            logger.error(
+                f"Failed to parse microformats for {url}: " f"got {resp.status_code}"
+            )
+            raise
 
     return mf2py.parse(doc=resp.text), resp.text