feat(calendar): libpst (readpst) download button in Settings, matching the Import dialog's tool buttons (FR-CAL-1, ADR-0008)

src/lib/views/Settings.svelte

@@ -286,6 +286,11 @@
   }
 
   // ---- Calendar / .pst import (T6.1/T6.2/T6.3, FR-CAL-1/2) ----
+  // .pst import shells out to readpst (libpst, ADR-0008) — external like
+  // ffmpeg/yt-dlp, so link the same kind of download button as the Import
+  // dialog's. ezwinports is the maintained Windows build of libpst.
+  const LIBPST_URL =
+    "https://sourceforge.net/projects/ezwinports/files/libpst-0.6.63-w32-bin.zip/download";
   let pstPath = $state("");
   let pstPassword = $state("");
   let eventTitleFilter = $state("");
@@ -987,7 +992,9 @@
           <p class="muted">{t("settings.hardware.stress_hint")}</p>
           <button onclick={runStressTest} disabled={stressRunning}>
             <Zap size={13} aria-hidden="true" />
-            {stressRunning ? t("settings.hardware.stress_running") : t("settings.hardware.stress_run")}
+            {stressRunning
+              ? t("settings.hardware.stress_running")
+              : t("settings.hardware.stress_run")}
           </button>
           {#if stressProgress}
             <p class="muted">{t("settings.hardware.stress_progress", { pair: stressProgress })}</p>
@@ -1344,6 +1351,12 @@
           {t("settings.calendar.intro_1")} <code>.pst</code>
           {t("settings.calendar.intro_2")}
         </p>
+        <div class="tools">
+          <span class="muted small">{t("settings.calendar.requires")}</span>
+          <button class="tool" type="button" onclick={() => api.openUrl(LIBPST_URL)}>
+            <Download size={12} aria-hidden="true" /> libpst (readpst)
+          </button>
+        </div>
         <div class="grid">
           <label class="wide"
             >{t("settings.calendar.pst_file")}
@@ -2384,6 +2397,33 @@
     font-size: 0.85rem;
     line-height: 1.5;
   }
+  /* External-tool download chip — identical to the Import dialog's
+     ffmpeg/yt-dlp buttons (ImportMeeting.svelte). */
+  .tools {
+    display: flex;
+    align-items: center;
+    flex-wrap: wrap;
+    gap: 0.4rem;
+    margin-top: 0.9rem;
+  }
+  .tool {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.25rem;
+    background: var(--bg-hover, transparent);
+    color: var(--accent);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    padding: 0.2rem 0.5rem;
+    font-size: 0.78rem;
+    cursor: pointer;
+  }
+  .tool:hover {
+    border-color: var(--accent);
+  }
+  .tools .small {
+    font-size: 0.8rem;
+  }
   .footnote {
     margin-top: 1rem;
     border-top: 1px solid var(--border);