send log: rows belong to a domain by id (audit L12, 0008)

A domain user's log, the message page, a domain's statistics, the level-2
count and the notifier's refusal count picked send-log rows by domain name,
so a domain deleted and re-added under its old name showed its earlier mail
to the next assignee and went on counting it.

Migration 0008 (not run on the live database yet, so extended here):
send_log.domain_id and inbound_spam_log.inbound_domain_id, REFERENCES ...
ON DELETE SET NULL, filled once by name from the registry as it is at
migration time, each with an (id, created_at) index.

- Writes: InsertQueued / InsertRejected set domain_id to the domain of the
  row's login (loginDomainID) - the journal milter and the sender check's
  refusal rows both go through them; the inbound journal sets
  inbound_domain_id from the inbound domain's name at insert.
- Reads: SendLogFilter.DomainIDs (was Domains, by name) and
  InboundSpamFilter.DomainIDs are the scope; the global role still reads
  everything. The message page checks row.DomainID against the user's
  domains. DomainSendStats and CountMessages keep their name argument and
  select domain_id = (SELECT id FROM domains WHERE name = ?). The notifier
  joins send_log.domain_id to the domain and its application.
- DMARC reports stay by name on purpose (a report is about the DNS name).

Tests: store - scope by ids; a re-added domain's log, level-2 count and
statistics hold its own row only, the global log both; inbound scope by
ids. Handlers - the new assignee gets 404 for the old row's page and does
not see it in the log, the global role sees both. Tests that wrote rows for
a login that is no application now register it (a row is a domain's through
its application). Schema at 0008 with the two columns and indexes.

schema-migrations row 8, CHANGELOG [Unreleased], audit plan line ticked,
roadmap 19/62.
Evidence: go vet ./... clean; go test ./... ok locally but for the two
Windows-only tests; the server run follows before the push.

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

internal/store/schema_test.go

@@ -47,7 +47,7 @@ func TestBaselineSchema(t *testing.T) {
 		"applications":          "id domain_id login address_mode auth_ip_restrict auth_allowed_ips created_at",
 		"application_addresses": "id application_id address",
 		"rate_limits":           "id scope ref_id max_messages window_seconds mode auto_multiplier auto_updated_at",
-		"send_log":              "id queue_id domain app_login from_addr to_addr subject status created_at updated_at reason header_from",
+		"send_log":              "id queue_id domain app_login from_addr to_addr subject status created_at updated_at reason header_from domain_id",
 		"logtail_state":         "path fingerprint read_offset updated_at",
 		"inbound_domains":       "id name recipient_mode created_at",
 		"inbound_transports":    "inbound_domain_id host port tls_mode",
@@ -55,7 +55,7 @@ func TestBaselineSchema(t *testing.T) {
 		"user_inbound_domains":  "user_id inbound_domain_id",
 		"dmarc_reports":         "id domain reporter report_id period_begin period_end received_at contact_email policy_p policy_sp policy_pct policy_adkim policy_aspf pass_count fail_count recipient",
 		"dmarc_report_records":  "id report_row_id source_ip count disposition spf_result dkim_result header_from",
-		"inbound_spam_log":      "id inbound_domain client_ip from_addr to_addr subject decision engine detail created_at",
+		"inbound_spam_log":      "id inbound_domain client_ip from_addr to_addr subject decision engine detail created_at inbound_domain_id",
 		"inbound_spam_list":     "id list_type entry_type value note created_at",
 		"send_log_lines":        "id queue_id logged_at line",
 		"notify_state":          "key phase count mark since sent_at",
@@ -105,8 +105,8 @@ func TestBaselineSchema(t *testing.T) {
 	rows.Close()
 	wantIdx := []string{
 		"idx_applications_login_nocase", "idx_dmarc_report_records_report", "idx_dmarc_reports_domain", "idx_dmarc_reports_received",
-		"idx_inbound_spam_log_created_at", "idx_inbound_spam_log_domain_created_at",
-		"idx_send_log_app_login_created_at", "idx_send_log_created_at", "idx_send_log_domain", "idx_send_log_lines_queue_id", "idx_send_log_queue_id", "idx_send_log_rejected",
+		"idx_inbound_spam_log_created_at", "idx_inbound_spam_log_domain_created_at", "idx_inbound_spam_log_domain_id_created_at",
+		"idx_send_log_app_login_created_at", "idx_send_log_created_at", "idx_send_log_domain", "idx_send_log_domain_id_created_at", "idx_send_log_lines_queue_id", "idx_send_log_queue_id", "idx_send_log_rejected",
 		"idx_sessions_expires_at",
 	}
 	sort.Strings(wantIdx)