fix(tests): resolve EntriesIsolationIntegrationTest failures with test-specific DB config

- Added `TestExposedConfiguration` to connect Exposed with Spring `DataSource` in the `test` profile.
- Downgraded `springdoc` version from `3.0.0` to `2.8.9` for Spring Boot 3.x compatibility.
- Applied `@ActiveProfiles("test")` to `EntriesIsolationIntegrationTest`.
- Updated roadmap documentation to reflect bugfix and test success.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

frontend/core/network/src/commonMain/kotlin/at/mocode/frontend/core/network/DomainErrors.kt

@@ -0,0 +1,19 @@
+package at.mocode.frontend.core.network
+
+/** HTTP 401 — Token abgelaufen oder ungültig. */
+class AuthExpired : RuntimeException("AUTH_EXPIRED")
+
+/** HTTP 403 — Zugriff verweigert. */
+class AuthForbidden : RuntimeException("AUTH_FORBIDDEN")
+
+/** HTTP 404 — Ressource nicht gefunden. */
+class NotFound : RuntimeException("NOT_FOUND")
+
+/** HTTP 409 — Konflikt (z. B. Duplikat). */
+class Conflict : RuntimeException("CONFLICT")
+
+/** HTTP 5xx — Serverfehler. */
+class ServerError : RuntimeException("SERVER_ERROR")
+
+/** Sonstiger HTTP-Fehler. */
+class HttpError(val code: Int) : RuntimeException("HTTP_$code")