feat: add Matrix chat notification support (#211)

Implements native Matrix notification channel support, allowing users
to receive service alerts in any Matrix room via the Client-Server API.

Changes:
- server/service-operation/notification/matrix.go: new Matrix service
  implementing the NotificationService interface (PUT /_matrix/client/v3/...)
- server/service-operation/notification/types.go: add MatrixHomeserver,
  MatrixRoomID, MatrixAccessToken fields to AlertConfiguration
- server/service-operation/notification/manager.go: register MatrixService
- server/pb_migrations/1772200000_updated_alert_configurations_matrix.js:
  PocketBase migration adding matrix fields and notification_type value
- application: Matrix option in channel dialog with homeserver/room/token
  fields, tab filter, list display, type definitions and translations (en, km)
- application/public/upload/notification/matrix.png: Matrix channel icon

application/src/components/settings/notification-settings/NotificationChannelDialog.tsx

@@ -38,7 +38,7 @@ interface NotificationChannelDialogProps {
 
 const baseSchema = z.object({
   notify_name: z.string().min(1, "Name is required"),
-  notification_type: z.enum(["telegram", "discord", "slack", "signal", "google_chat", "email", "ntfy", "pushover", "notifiarr", "gotify", "webhook"]),
+  notification_type: z.enum(["telegram", "discord", "slack", "signal", "google_chat", "email", "ntfy", "pushover", "notifiarr", "gotify", "webhook", "matrix"]),
   enabled: z.boolean().default(true),
   service_id: z.string().default("global"),
   template_id: z.string().optional(),
@@ -110,6 +110,13 @@ const gotifySchema = baseSchema.extend({
   server_url: z.string().url("Must be a valid server URL"),
 });
 
+const matrixSchema = baseSchema.extend({
+  notification_type: z.literal("matrix"),
+  matrix_homeserver: z.string().url("Must be a valid homeserver URL"),
+  matrix_room_id: z.string().min(1, "Room ID is required"),
+  matrix_access_token: z.string().min(1, "Access token is required"),
+});
+
 const formSchema = z.discriminatedUnion("notification_type", [
   telegramSchema,
   discordSchema,
@@ -122,6 +129,7 @@ const formSchema = z.discriminatedUnion("notification_type", [
   notifiarrSchema,
   gotifySchema,
   webhookSchema,
+  matrixSchema,
 ]);
 
 type FormValues = z.infer<typeof formSchema>;
@@ -188,12 +196,18 @@ const notificationTypeOptions = [
     description: "Send push notifications via Gotify",
     icon: "/upload/notification/gotify.png" 
   },
-  { 
-    value: "webhook", 
-    label: "Webhook", 
+  {
+    value: "webhook",
+    label: "Webhook",
     description: "Send notifications to custom webhook",
     icon: "/upload/notification/webhook.png"
   },
+  {
+    value: "matrix",
+    label: "Matrix",
+    description: "Send notifications to a Matrix chat room",
+    icon: "/upload/notification/matrix.png"
+  },
 ];
 
 const webhookPayloadTemplates = {
@@ -832,6 +846,59 @@ export const NotificationChannelDialog = ({
               </>
             )}
             
+            {notificationType === "matrix" && (
+              <>
+                <FormField
+                  control={form.control}
+                  name="matrix_homeserver"
+                  render={({ field }) => (
+                    <FormItem>
+                      <FormLabel>{t("matrixHomeserver")}</FormLabel>
+                      <FormControl>
+                        <Input placeholder={t("matrixHomeserverPlaceholder")} {...field} />
+                      </FormControl>
+                      <FormDescription>
+                        {t("matrixHomeserverDesc")}
+                      </FormDescription>
+                      <FormMessage />
+                    </FormItem>
+                  )}
+                />
+                <FormField
+                  control={form.control}
+                  name="matrix_room_id"
+                  render={({ field }) => (
+                    <FormItem>
+                      <FormLabel>{t("matrixRoomId")}</FormLabel>
+                      <FormControl>
+                        <Input placeholder={t("matrixRoomIdPlaceholder")} {...field} />
+                      </FormControl>
+                      <FormDescription>
+                        {t("matrixRoomIdDesc")}
+                      </FormDescription>
+                      <FormMessage />
+                    </FormItem>
+                  )}
+                />
+                <FormField
+                  control={form.control}
+                  name="matrix_access_token"
+                  render={({ field }) => (
+                    <FormItem>
+                      <FormLabel>{t("matrixAccessToken")}</FormLabel>
+                      <FormControl>
+                        <Input placeholder={t("matrixAccessTokenPlaceholder")} {...field} type="password" />
+                      </FormControl>
+                      <FormDescription>
+                        {t("matrixAccessTokenDesc")}
+                      </FormDescription>
+                      <FormMessage />
+                    </FormItem>
+                  )}
+                />
+              </>
+            )}
+
             <FormField
               control={form.control}
               name="enabled"

application/src/components/settings/notification-settings/NotificationChannelList.tsx

@@ -82,6 +82,7 @@ export const NotificationChannelList = ({
       case "pushover": return "Pushover";
       case "notifiarr": return "Notifiarr";
       case "webhook": return "Webhook";
+      case "matrix": return "Matrix";
       default: return type || "Unknown";
     }
   };
@@ -102,6 +103,8 @@ export const NotificationChannelList = ({
         return config.signal_number || '';
       case "email":
         return config.email_address || '';
+      case "matrix":
+        return config.matrix_room_id || '';
       default:
         return '';
     }

application/src/components/settings/notification-settings/NotificationSettings.tsx

@@ -154,6 +154,7 @@ const NotificationSettings = () => {
             <TabsTrigger value="google_chat">{t("googleChat")}</TabsTrigger>
             <TabsTrigger value="email">{t("email")}</TabsTrigger>
             <TabsTrigger value="webhook">{t("webhook")}</TabsTrigger>
+            <TabsTrigger value="matrix">{t("matrix")}</TabsTrigger>
           </TabsList>
           
           <TabsContent value={currentTab} className="mt-0">