fix: CalDAV Nextcloud — fallback principals/users/ pour calendar-home-set (v0.0.2)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/main/java/com/planify/mobile/data/caldav/CalDavDiscovery.kt

@@ -94,10 +94,20 @@ class CalDavDiscovery @Inject constructor(private val client: CalDavClient) {
             </propfind>
         """.trimIndent()
 
-        val resp = client.propfind(principalUrl, credentials, "0", body)
-        if (!resp.isSuccess) return null
-        val href = extractHref(resp.body, "calendar-home-set") ?: return null
-        return resolveUrl(principalUrl, href)
+        val urlsToTry = mutableListOf(principalUrl)
+        // Nextcloud alias /principals/username/ doesn't expose calendar-home-set,
+        // but /principals/users/username/ does — add it as fallback
+        if (principalUrl.contains("/principals/") && !principalUrl.contains("/principals/users/")) {
+            urlsToTry.add(principalUrl.replaceFirst("/principals/", "/principals/users/"))
+        }
+
+        for (url in urlsToTry) {
+            val resp = client.propfind(url, credentials, "0", body)
+            if (!resp.isSuccess) continue
+            val href = extractHref(resp.body, "calendar-home-set") ?: continue
+            return resolveUrl(url, href)
+        }
+        return null
     }
 
     private fun listCalendars(homeUrl: String, credentials: String, username: String, baseUrl: String): List<CalendarInfo> {