bloom: raise max_inbound_fpr antipoison cap from 0.05 to 0.10

The inbound FilterAnnounce FPR cap rejects filters whose false-positive
rate (fill^k) exceeds the configured maximum. On the fixed 1 KB / k=5
filter, 0.05 corresponds to fill 0.549 (~1,300 reachable entries), and
the busiest nodes' aggregates were beginning to hit that ceiling as the
mesh grew. Raise the default to 0.10 (fill 0.631, ~1,630 entries) to
restore headroom toward the fixed-filter capacity limit. A saturated or
poisoned filter is ~100% FPR and remains rejected, so the antipoison
gate is not materially weakened.

Updates the config default, the config-reference and bloom-filter
design docs, and the changelog.

CHANGELOG.md

@@ -32,6 +32,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- `node.bloom.max_inbound_fpr` default raised from `0.05` to `0.10`. The
+  cap rejects inbound `FilterAnnounce` whose FPR (`fill^k`) exceeds it. On
+  the fixed 1 KB / k=5 filter, `0.05` corresponds to fill 0.549 (~1,300
+  reachable entries) and had begun rejecting the busiest nodes' aggregates
+  as the mesh approached that size. `0.10` (fill 0.631, ~1,630 entries)
+  restores headroom toward the fixed-filter capacity limit without
+  materially weakening the antipoison gate: a saturated or poisoned filter
+  is ~100% FPR and still rejected.
 - Sidecar example (`examples/sidecar-nostr-relay`): `udp.mtu` is now
   overridable via the `FIPS_UDP_MTU` environment variable, defaulting to
   1472 (preserving prior behavior). Plumbed through `docker-compose.yml`