New reverse zone: pick from the networks your records use, sized around them

The Zones page's New reverse zone lists every network the records use without a reverse zone, in every view, also where nothing is suggested (suggestions off, dismissed, public views), marked. Picking one fills in the network and view; size buttons (/48 /56 /64 /128, /16 /24 /32) re-mask it around a record's address, so a /48 becomes the records' own /64. Fill stays on. jarl zone suggest-reverse --all [--view V]; GET /reverse-zones/suggestions?all=1&view=.

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

scripts/e2e.sh

@@ -705,6 +705,8 @@ not_contains "^yours"
 run "a view can turn suggestions off" 0 $J view update internal --reverse-suggestions=false
 run "then none for it" 0 $J zone suggest-reverse
 not_contains "internal"
+run "but --all still lists its networks" 0 $J zone suggest-reverse --all --view internal
+contains "^public  *internal  *185.199.108.153/32 .* suggestions off"
 run "and back on" 0 $J view update internal --reverse-suggestions
 # A zone created inside another takes the parent's records under it.
 run "a /16 reverse zone" 0 $J zone create 10.88.0.0/16 --view internal