Set a user's web UI password from the Users section

terdut-server v0.10.2 serves a web UI you sign in to with a password,
and every user starts without one. Until now the only way to give
somebody their first password was a curl call with an API key. p in
Users sets the selected user's password.

The form asks for the current password only in the one case the server
checks it: you are changing your own password and already have one. The
client has no other way to know who its key belongs to, so opening the
form calls GET /api/me first and shows the fields once that answers.
Setting someone else's password sends no current_password at all,
rather than an empty one.

Length (at least 10) and the repeated entry are checked before anything
is sent, mirroring the server's rule so a typo costs no round trip. The
server stays authoritative: a wrong current password comes back as its
own 403 message on the dashboard. The status line says the user's other
web sessions were signed out, because the server does that on every
password change. API keys are not affected.

Older servers have no /api/me. The client now returns a typed
StatusError carrying the status code, so a 404 there reads as "needs
terdut-server v0.10.2 or later" rather than a bare "server returned
404". Its Error() text is unchanged, so every existing message reads as
before.

Requires terdut-server v0.10.2 only for this form. Everything else works
against the same servers as before.

internal/tui/users_test.go

@@ -1,6 +1,7 @@
 package tui
 
 import (
+	"strings"
 	"testing"
 	"time"
 
@@ -81,4 +82,123 @@ func TestUsers_ArrowKeysStillNavigate(t *testing.T) {
 	}
 }
 
+func TestPassword_OpensForTheSelectedUserAndLooksUpWhoIAm(t *testing.T) {
+	m, cmd := press(t, threeUsers(), "p")
+	if m.mode != modePasswordSet || m.selectedUser.Username != "erik" {
+		t.Fatalf("expected the password form for erik, got mode %v for %q", m.mode, m.selectedUser.Username)
+	}
+	if !m.pwLoading || cmd == nil {
+		t.Error("the form should look up /api/me before it is usable")
+	}
+	if !strings.Contains(m.View(), "Checking who this key belongs to") {
+		t.Error("the form should say it is waiting")
+	}
+}
+
+func TestPassword_SomeoneElseNeedsNoCurrentPassword(t *testing.T) {
+	m, _ := press(t, threeUsers(), "p")
+	next, _ := m.Update(meFetchedMsg{me: api.Me{User: api.User{ID: 1}, HasPassword: true}})
+	m = next.(Model)
+	if m.pwNeedCurrent || m.pwFocus != pwNew {
+		t.Errorf("setting erik's password as niklas should not ask for a current one")
+	}
+	if strings.Contains(m.View(), "Current password") {
+		t.Error("the current-password field should be hidden")
+	}
+}
+
+func TestPassword_OwnExistingPasswordNeedsCurrent(t *testing.T) {
+	m := threeUsers()
+	m.userManageTable.SetCursor(0)
+	m, _ = press(t, m, "p")
+	next, _ := m.Update(meFetchedMsg{me: api.Me{User: api.User{ID: 1}, HasPassword: true}})
+	m = next.(Model)
+	if !m.pwNeedCurrent || m.pwFocus != pwCurrent {
+		t.Fatal("changing your own existing password should ask for the current one first")
+	}
+	m = typeInto(t, m, "correct horse")
+	m, _ = press(t, m, "tab")
+	m = typeInto(t, m, "a brand new secret")
+	m, _ = press(t, m, "tab")
+	m = typeInto(t, m, "a brand new secret")
+	m, cmd := press(t, m, "enter")
+	if cmd == nil || m.mode != modeDashboard {
+		t.Errorf("a complete form should submit (mode %v)", m.mode)
+	}
+}
+
+func TestPassword_OwnFirstPasswordNeedsNoCurrent(t *testing.T) {
+	m := threeUsers()
+	m.userManageTable.SetCursor(0)
+	m, _ = press(t, m, "p")
+	next, _ := m.Update(meFetchedMsg{me: api.Me{User: api.User{ID: 1}, HasPassword: false}})
+	if next.(Model).pwNeedCurrent {
+		t.Error("there is no current password to ask for yet")
+	}
+}
+
+func TestPassword_RejectsBeforeSending(t *testing.T) {
+	cases := []struct{ name, pw, repeat, want string }{
+		{"too short", "short", "short", "at least 10"},
+		{"mismatch", "a brand new secret", "a different secret", "do not match"},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			m, _ := press(t, threeUsers(), "p")
+			next, _ := m.Update(meFetchedMsg{me: api.Me{User: api.User{ID: 1}}})
+			m = typeInto(t, next.(Model), tc.pw)
+			m, _ = press(t, m, "tab")
+			m = typeInto(t, m, tc.repeat)
+			m, cmd := press(t, m, "enter")
+			if m.mode != modePasswordSet {
+				t.Error("the form should stay open")
+			}
+			if !strings.Contains(m.statusMsg, tc.want) {
+				t.Errorf("status %q should mention %q", m.statusMsg, tc.want)
+			}
+			if cmd == nil {
+				return
+			}
+			// Only the clear-status timer may be scheduled, never a request.
+			if _, ok := cmd().(clearStatusMsg); !ok {
+				t.Error("nothing should be sent to the server")
+			}
+		})
+	}
+}
+
+func TestPassword_EscapeCancels(t *testing.T) {
+	m, _ := press(t, threeUsers(), "p")
+	m, _ = press(t, m, "esc")
+	if m.mode != modeDashboard {
+		t.Errorf("esc should close the form, got mode %v", m.mode)
+	}
+	// A lookup arriving after the form closed must not reopen anything.
+	next, _ := m.Update(meFetchedMsg{me: api.Me{User: api.User{ID: 3}, HasPassword: true}})
+	if next.(Model).mode != modeDashboard {
+		t.Error("a late /api/me answer reopened the form")
+	}
+}
+
+func TestPassword_ErrorClosesTheFormWithAMessage(t *testing.T) {
+	m, _ := press(t, threeUsers(), "p")
+	next, _ := m.Update(userActionErrMsg{errTest("server returned 403: current password is incorrect")})
+	m = next.(Model)
+	if m.mode != modeDashboard || !strings.Contains(m.statusMsg, "current password is incorrect") {
+		t.Errorf("expected the server's message on the dashboard, got %q in mode %v", m.statusMsg, m.mode)
+	}
+}
+
+func typeInto(t *testing.T, m Model, s string) Model {
+	t.Helper()
+	next, _ := m.Update(runes(s))
+	return next.(Model)
+}
+
+func runes(s string) tea.KeyMsg { return tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune(s)} }
+
 func keyUp() tea.KeyMsg { return tea.KeyMsg{Type: tea.KeyUp} }
+
+type errTest string
+
+func (e errTest) Error() string { return string(e) }