feat: P2.9 VNCtalk + P2.10 Collabora + P2.11 Calendar Enhancements + P2.13 VNCdirectory Admin

- P2.9: VNCtalk video meeting — create/update meeting from event modal,
  'Join Meeting' link in event detail. Admin config vnctalkServerUrl.
- P2.10: Collabora online editing — 'Edit with Collabora' for office files,
  WOPI discovery + edit URL. Admin config collaboraServerUrl.
- P2.11: Calendar enhancements — clickable links in descriptions,
  participant contact popover, Reply/Reply All from event, timezone picker,
  map links for locations.
- P2.13: VNCdirectory IDP admin panel — Connection, SAML/IDP, LDAP,
  Authentication, Federated Apps configuration. Secret masking on display.

lib/vnctalk/client.ts

@@ -0,0 +1,56 @@
+import { configManager } from "@/lib/admin/config-manager";
+
+export interface CreateVncMeetingParams {
+  name: string;
+  start: string;
+  end: string;
+  invitees: string[];
+  password?: string;
+  description?: string;
+}
+
+export interface CreateVncMeetingResult {
+  meetingUrl: string;
+  meetingId: string;
+}
+
+export async function createVncMeeting(
+  params: CreateVncMeetingParams
+): Promise<CreateVncMeetingResult> {
+  const serverUrl = configManager.get<string>("vnctalkServerUrl") || process.env.VNCTALK_SERVER_URL || "";
+
+  if (!serverUrl) {
+    throw new Error("VNCTALK_SERVER_URL is not configured");
+  }
+
+  const endpoint = `${serverUrl.replace(/\/+$/, "")}/api/createnewmeeting`;
+
+  const response = await fetch(endpoint, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({
+      name: params.name,
+      start: params.start,
+      end: params.end,
+      invitees: params.invitees,
+      password: params.password,
+      description: params.description,
+    }),
+  });
+
+  if (!response.ok) {
+    const text = await response.text().catch(() => "");
+    throw new Error(`VNCtalk API error ${response.status}: ${text}`);
+  }
+
+  const data = await response.json();
+
+  const meetingUrl: string = data.meetingUrl || data.meeting_url || data.url || "";
+  const meetingId: string = data.meetingId || data.meeting_id || data.id || "";
+
+  if (!meetingUrl) {
+    throw new Error("VNCtalk API did not return a meeting URL");
+  }
+
+  return { meetingUrl, meetingId };
+}