feat(settings): SSO account guard + remove redundant Office Days

- Account tab: SSO users see an info banner instead of email/password forms
- Briefing tab: remove Office Days section (work days now come from Profile)
- Remove unused toggleWorkDay function

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/views/SettingsView.vue

@@ -347,13 +347,6 @@ async function geocodeLocation(key: 'home' | 'work') {
   }
 }
 
-function toggleWorkDay(day: number) {
-  const days = briefingConfig.value.work_days;
-  const idx = days.indexOf(day);
-  if (idx === -1) days.push(day);
-  else days.splice(idx, 1);
-  days.sort();
-}
 
 
 async function saveBriefingSettings() {
@@ -1578,6 +1571,16 @@ function formatUserDate(iso: string): string {
     <!-- ── Account ── -->
     <div v-show="activeTab === 'account'" class="settings-grid">
 
+      <!-- SSO accounts: no local credential management -->
+      <section v-if="!authStore.user?.has_password" class="settings-section">
+        <h2>Account</h2>
+        <p class="section-desc">
+          Your account is managed by an external identity provider.
+          Email and password changes are made through your provider, not here.
+        </p>
+      </section>
+
+      <template v-if="authStore.user?.has_password">
         <section class="settings-section">
           <h2>Email Address</h2>
           <p class="section-desc">Used for password resets and notifications.</p>
@@ -1591,7 +1594,7 @@ function formatUserDate(iso: string): string {
               class="input"
             />
           </div>
-        <div v-if="authStore.user?.has_password" class="field">
+          <div class="field">
             <label for="email-password">Current Password</label>
             <input
               id="email-password"
@@ -1606,7 +1609,7 @@ function formatUserDate(iso: string): string {
             <button
               class="btn-save"
               @click="changeEmail"
-            :disabled="changingEmail || (authStore.user?.has_password && !emailPassword)"
+              :disabled="changingEmail || !emailPassword"
             >
               {{ changingEmail ? "Saving..." : "Save Email" }}
             </button>
@@ -1660,11 +1663,12 @@ function formatUserDate(iso: string): string {
             </button>
           </div>
         </section>
+      </template>
 
       <section class="settings-section">
         <h2>Active Sessions</h2>
         <p class="section-desc">
-          Sign out all other devices and sessions. Use this after an SSO password change
+          Sign out all other devices and sessions. Use this after a password change
           to ensure stale sessions are revoked.
         </p>
         <div class="actions">
@@ -2112,21 +2116,6 @@ function formatUserDate(iso: string): string {
         </div>
       </section>
 
-      <!-- Work schedule -->
-      <section class="settings-section full-width">
-        <h2>Office Days</h2>
-        <p class="section-desc">Which days do you go into the office? Used to decide whether to include the 8am check-in slot.</p>
-        <div class="briefing-day-toggles">
-          <button
-            v-for="(day, idx) in ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']"
-            :key="idx"
-            :class="['briefing-day-btn', { active: briefingConfig.work_days.includes(idx) }]"
-            @click="toggleWorkDay(idx)"
-            type="button"
-          >{{ day }}</button>
-        </div>
-      </section>
-
       <!-- Slots -->
       <section class="settings-section full-width">
         <h2>Scheduled Slots</h2>