fix(xff): truncate LEAKED IPs + ROTATION badge for rotation attacks

`for i in $(seq 1 100); do curl -H "X-Forwarded-For: 191.100.20.$i" ...`
was dumping 100 distinct IPs into AttackerDetail's LEAKED IPs row,
drowning the rest of the ORIGIN section. The 100-IP wall is itself a
signal (WAF-bypass-list probing) that deserves a short badge, not a
flood.

Backend:
- get_attacker_ip_leaks gains `limit: int = 10` parameter — caller
  only ever needs a sample, not the full set.
- New count_attacker_ip_leaks() returns the unbounded COUNT(*) via
  one cheap SQL aggregate.
- Detail endpoint returns {ip_leaks: [first 10], ip_leaks_total: N}
  so the UI can render a rotation badge independent of list length.

UI:
- New LeakedIPsRow component. First 5 distinct IPs rendered inline
  with hover tooltips (unchanged). When > 5, a `+ N more` expand
  button reveals the rest of the sample; when total exceeds the
  10-row cap, a subtle `(+M beyond sample)` note appears.
- When total ≥ 20, a red `ROTATION · N` tag renders leading the
  row with a tooltip explaining the semantic: "almost certainly
  XFF-rotation / WAF-bypass probing, not a real attribution leak."

DB churn is deliberately not capped — 100k rows × ~500 B is tolerable.
If it becomes a problem we can add an ingester-side count-and-skip;
for now the UX fix is the whole story.

Added test_ip_leaks_total_reported_separately_from_list asserting
the endpoint shape matches what the UI consumes.

decnet/web/db/repository.py

@@ -258,12 +258,20 @@ class BaseRepository(ABC):
         raise NotImplementedError
 
     async def get_attacker_ip_leaks(
-        self, attacker_uuid: str
+        self, attacker_uuid: str, *, limit: int = 10,
     ) -> list[dict[str, Any]]:
-        """Return ``bounty_type='ip_leak'`` rows for the attacker, newest
-        first. Each row's payload carries the TCP source IP, the header
-        that leaked, and the claimed real IP — see the XFF-mismatch
-        extractor in ``decnet.web.ingester`` for the shape."""
+        """Return up to ``limit`` ``bounty_type='ip_leak'`` rows for the
+        attacker, newest first. Each row's payload carries the TCP
+        source IP, the header that leaked, and the claimed real IP —
+        see the XFF-mismatch extractor in ``decnet.web.ingester`` for
+        the shape. Caller pairs with :meth:`count_attacker_ip_leaks`
+        to detect XFF-rotation (100+ claimed IPs from one source)."""
+        raise NotImplementedError
+
+    async def count_attacker_ip_leaks(self, attacker_uuid: str) -> int:
+        """Total number of ``ip_leak`` bounties recorded for this
+        attacker. Used to detect XFF-rotation signal where the attacker
+        cycles through many claimed IPs (WAF-bypass-list probing)."""
         raise NotImplementedError
 
     @abstractmethod