feat(ui): encryption-vault panel in Settings privacy (enable/unlock/lock/change) (T8.8)

src/lib/views/Settings.svelte

@@ -63,6 +63,58 @@
   let showConsent = $state(false);
   let testResult = $state<{ ok: boolean; message: string } | null>(null);
 
+  // ---- At-rest encryption vault (T8.8, FR-SEC-3) ----
+  let vault = $state<{ enabled: boolean; unlocked: boolean } | null>(null);
+  let vaultPw = $state("");
+  let vaultPw2 = $state("");
+  let vaultMsg = $state<string | null>(null);
+  async function loadVault() {
+    try {
+      vault = await api.vaultStatus();
+    } catch {
+      vault = null;
+    }
+  }
+  onMount(loadVault);
+  async function enableVault() {
+    vaultMsg = null;
+    try {
+      await api.enableVault(vaultPw);
+      vaultPw = "";
+      vaultMsg = "Vault enabled and unlocked.";
+      await loadVault();
+    } catch (e) {
+      vaultMsg = `${e}`;
+    }
+  }
+  async function unlockVault() {
+    vaultMsg = null;
+    try {
+      await api.unlockVault(vaultPw);
+      vaultPw = "";
+      vaultMsg = "Unlocked.";
+      await loadVault();
+    } catch (e) {
+      vaultMsg = `${e}`;
+    }
+  }
+  async function lockVault() {
+    await api.lockVault();
+    vaultMsg = "Locked.";
+    await loadVault();
+  }
+  async function changeVaultPassword() {
+    vaultMsg = null;
+    try {
+      await api.changeVaultPassword(vaultPw, vaultPw2);
+      vaultPw = "";
+      vaultPw2 = "";
+      vaultMsg = "Password changed.";
+    } catch (e) {
+      vaultMsg = `${e}`;
+    }
+  }
+
   // ---- NPU package download (T3.4) ----
   let npuBusy = $state(false);
   let npuMsg = $state<string | null>(null);
@@ -612,6 +664,56 @@
         {:else}
           <p class="muted">Privacy self-check unavailable.</p>
         {/if}
+
+        {#if vault}
+          <h4>Encryption vault</h4>
+          {#if !vault.enabled}
+            <p class="muted">
+              Encrypt notes, transcripts, and summaries at rest with a password. (Audio files are
+              not encrypted yet.)
+            </p>
+            <div class="grid">
+              <label class="wide"
+                >Vault password<input type="password" bind:value={vaultPw} /></label
+              >
+            </div>
+            <button class="primary" onclick={enableVault} disabled={vaultPw.length < 8}
+              >Enable vault</button
+            >
+            <p class="muted">
+              Use at least 8 characters. If you forget it, encrypted content can't be recovered.
+            </p>
+          {:else if !vault.unlocked}
+            <p class="muted">
+              Vault is <strong>locked</strong>. Unlock to read encrypted meetings.
+            </p>
+            <div class="grid">
+              <label class="wide">Password<input type="password" bind:value={vaultPw} /></label>
+            </div>
+            <button class="primary" onclick={unlockVault} disabled={!vaultPw}>Unlock</button>
+          {:else}
+            <p class="muted">
+              Vault is <strong>unlocked</strong>. New notes, transcripts, and summaries are
+              encrypted at rest.
+            </p>
+            <button onclick={lockVault}>Lock now</button>
+            <details>
+              <summary>Change password</summary>
+              <div class="grid">
+                <label class="wide"
+                  >Current password<input type="password" bind:value={vaultPw} /></label
+                >
+                <label class="wide"
+                  >New password<input type="password" bind:value={vaultPw2} /></label
+                >
+              </div>
+              <button onclick={changeVaultPassword} disabled={!vaultPw || vaultPw2.length < 8}
+                >Change password</button
+              >
+            </details>
+          {/if}
+          {#if vaultMsg}<p class="muted">{vaultMsg}</p>{/if}
+        {/if}
       </section>
     {/if}
   </div>