Quotas: reset one address, or give some back

POST /rules/{ref}/reset-quota takes an optional address (one entry of a
per-address quota starts again) and give (bytes taken off what was used,
one address's or everyone's, until the next reset). The firewall keeps
the adjustment for its next apply, which writes the new usage into the
ruleset; housecarld applies at once and saves the usage. hc rule
reset-quota --address/--give; Reset and Give back in the web UI, per
address in the usage dialog.

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

scripts/e2e.sh

@@ -327,10 +327,21 @@ stop; start
 run "after a restart, still used up" 1 send 1000
 run "the usage after a restart" 0 H quotas
 contains "$CLIENT4 (e2e-client)  *1\.[0-9] MB"
+# A top-up: some given back (more than the cut-off packets added), then
+# used up again; one address started again; then the whole quota.
+run "a top-up for the device" 0 H rule reset-quota "$QR" --give 10mbytes --address $CLIENT4
+contains "gave back 10.0 MB"
+run "topped up: the device is back" 0 send 1000
+send 30000000 >/dev/null 2>&1
+run "used up again" 1 send 1000
+run "an address that used nothing" 4 H rule reset-quota "$QR" --address 10.88.10.99
+run "one address started again" 0 H rule reset-quota "$QR" --address $CLIENT4
+run "back again" 0 send 1000
 run "reset by hand" 0 H rule reset-quota "$QR"
 run "the device is back" 0 send 1000
 run "the reset is audited" 0 H audit --action quota.
 contains "quota.reset"
+contains "quota.give"
 run "the quota rule goes" 0 H rule delete -y "$QR"
 
 # ---- the zone matrix, of the imported ruleset