panel-redesign: security review of 2.0 - sessions belong to a user by id

Stage 3, step 2. Reviewed by Fable (read-only), fixed by Sonnet with a
failing test before each fix, checked by Opus. No Critical or High
finding: route authorization, tenant isolation by id, the /server/
subtree guard, output encoding and the origin check were found sound.

Fixed
  - M1: a session was keyed by user name and had no link to the user. A
    deleted or renamed user's cookie stayed alive (renewed on every hit,
    before the user was looked up) and became a session of whoever was
    later created under that name, with that account's role. The
    baseline now has sessions.user_id REFERENCES users(id) ON DELETE
    CASCADE; the principal is resolved by id and a session is renewed
    only after its user was found. RenameSession is gone.
  - M2: any user's password change deleted every other user's sessions.
    It ends that user's other sessions only.
  - L1: a password set on the user form ends that user's sessions (an
    administrator editing their own account keeps the current one).
  - L2: store, saslpasswd2 and Postfix reload errors were shown verbatim
    on the application form, the inbound upstream / recipients forms and
    the limit recalculation - pages a domain administrator reaches.
    Validation errors (app.ValidationError, inbound.ValidationError,
    store.ErrNotAutoRateLimit) keep their text; anything else is logged
    and shown as "Could not save ... Check the logs and try again."
  - L3: store.ListDMARCReports treated an empty domain list as "all". It
    takes a scope now (AllDomains or a list; an empty list is no rows),
    and the DMARC hub is open to the domain role as the plan says: the
    reports of the assigned domains, without the instance-wide ingest
    box. The menu entry was already shown to them and led to a 404.
  - I1: /static/ answered with a listing of the embedded assets. A path
    that is not a known asset is a 404.

Consequences
  - The global DMARC hub lists reports of domains that were deleted
    since, too.
  - dev/migrate1x (not in the tree) no longer carries sessions over:
    everyone signs in again after the transfer.
  - docs/schema-migrations.md: the sessions row.

Recorded, not changed - for the owner:
  - L4: the report-address select names the followed user and their
    address to every administrator of the domain, by default the global
    administrator's login name. The plan asks for it.
  - L5: a delegated inbound upstream may be any host and port, loopback
    and private ranges included - within the trusted-operator model; to
    be listed among the accepted risks in security.md.
  - L6: Account's profile is saved without the password; becomes a
    requirement once password-reset mails to users.email.
  - Still echoing an error's text: backup and domain import (global
    only), the domain form's validation messages.

Not checked by the review: anything needing the container (e2e, real
Postfix / DNS), CSP behaviour in a live browser.

  go test -count=1 ./internal/web/... ./internal/store/... ./internal/app/...
    ./internal/inbound/... ./internal/dmarc/... ./cmd/panel
      ok  (all eleven packages; dev/migrate1x also ok)

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

internal/store/dmarc_test.go

@@ -29,7 +29,7 @@ func TestDMARCReportRoundTrip(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	list, err := st.ListDMARCReports([]string{"example.com"}, 10)
+	list, err := st.ListDMARCReports(DMARCReportScope{Domains: []string{"example.com"}}, 10)
 	if err != nil || len(list) != 1 {
 		t.Fatalf("list: %v err=%v", list, err)
 	}
@@ -61,8 +61,48 @@ func TestPruneDMARCReports(t *testing.T) {
 	if err := st.PruneDMARCReports(); err != nil {
 		t.Fatal(err)
 	}
-	list, _ := st.ListDMARCReports(nil, 100)
+	list, _ := st.ListDMARCReports(DMARCReportScope{AllDomains: true}, 100)
 	if len(list) != 0 {
 		t.Fatalf("expected prune by age, got %d", len(list))
 	}
 }
+
+// The domains a list is limited to are the whole answer: an empty list is a
+// viewer who reaches nothing, never a viewer who reaches everything.
+func TestListDMARCReportsEmptyListIsNoRows(t *testing.T) {
+	st := openTestStore(t)
+	now := time.Now().UTC()
+	for _, domain := range []string{"a.example", "b.example"} {
+		if _, err := st.InsertDMARCReport(DMARCReport{
+			Domain: domain, Reporter: "r", ReportID: domain,
+			PeriodBegin: now.Add(-24 * time.Hour), PeriodEnd: now, ReceivedAt: now,
+		}); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	for name, scope := range map[string]DMARCReportScope{
+		"an empty list":   {Domains: []string{}},
+		"no scope at all": {},
+	} {
+		list, err := st.ListDMARCReports(scope, 10)
+		if err != nil {
+			t.Fatalf("%s is an error: %v", name, err)
+		}
+		if len(list) != 0 {
+			t.Errorf("%s returned %d report(s), want none", name, len(list))
+		}
+	}
+	list, err := st.ListDMARCReports(DMARCReportScope{Domains: []string{"a.example"}}, 10)
+	if err != nil || len(list) != 1 || list[0].Domain != "a.example" {
+		t.Errorf("one domain = %+v, %v; want only a.example", list, err)
+	}
+	list, err = st.ListDMARCReports(DMARCReportScope{AllDomains: true}, 10)
+	if err != nil || len(list) != 2 {
+		t.Errorf("all domains = %d report(s), %v; want both", len(list), err)
+	}
+	list, err = st.ListDMARCReports(DMARCReportScope{AllDomains: true, Domains: []string{"a.example"}}, 10)
+	if err != nil || len(list) != 2 {
+		t.Errorf("all domains with a list = %d report(s), %v; want both (AllDomains wins)", len(list), err)
+	}
+}