Add calendar store for imported events and PST import progress state

src/lib/stores/calendar.svelte.ts

@@ -0,0 +1,41 @@
+// Imported calendar events (Phase 6, FR-CAL-*). Svelte 5 runes store, same
+// shape as settings.svelte.ts/meetings.svelte.ts.
+
+import { api, events, type CalendarEvent } from "../api";
+
+class CalendarStore {
+  events = $state<CalendarEvent[]>([]);
+  loaded = $state(false);
+  importing = $state(false);
+  importProgress = $state<{ processed: number; total: number } | null>(null);
+  importError = $state<string | null>(null);
+
+  async load() {
+    try {
+      this.events = await api.listCalendarEvents();
+    } catch {
+      this.events = []; // no .pst imported yet, or command unreachable
+    }
+    if (!this.loaded) {
+      await events.onPstProgress((p) => (this.importProgress = p));
+      this.loaded = true;
+    }
+  }
+
+  async importPst(path: string, password?: string) {
+    this.importing = true;
+    this.importError = null;
+    this.importProgress = null;
+    try {
+      await api.importPst(path, password);
+      await this.load();
+    } catch (e) {
+      this.importError = e instanceof Error ? e.message : String(e);
+    } finally {
+      this.importing = false;
+      this.importProgress = null;
+    }
+  }
+}
+
+export const calendar = new CalendarStore();