Make OpenApiRouteBuilder spec path cross-platform

The auto-built OpenAPI route embeds specFile.getAbsolutePath() into an EL
`${read('...')}` string literal for the validator and mock-handler config.
On Windows the absolute path uses the '\' separator, which the EL parser
treats as an (invalid) escape sequence, so the generated route fails to parse
and never loads. Normalise the platform separator to '/', which read()/File
accept on every OS (no-op on Linux/macOS).

Author: vharseko

openig-core/src/main/java/org/forgerock/openig/handler/router/OpenApiRouteBuilder.java

@@ -108,9 +108,15 @@ public JsonValue buildRouteJson(final OpenAPI spec, final File specFile,
                 routeName, specFile.getName(), condition, baseUri != null ? baseUri : "<none>",
                 failOnResponseViolation, mockMode);
 
+        // Normalise the platform path separator to '/': this path is embedded in an EL
+        // read('...') string literal, where a Windows backslash (D:\...) is parsed as an
+        // (invalid) escape sequence. Forward slashes are accepted by read()/File on every OS.
+        final String absolutePath = specFile.getAbsolutePath();
+        final String specPath = absolutePath == null ? null : absolutePath.replace(File.separatorChar, '/');
+
         // ----- heap: OpenApiValidationFilter entry -----
         final Map<String, Object> validatorConfig = new LinkedHashMap<>();
-        validatorConfig.put("spec", "${read('" + specFile.getAbsolutePath() + "')}");
+        validatorConfig.put("spec", "${read('" + specPath + "')}");
         validatorConfig.put("failOnResponseViolation", failOnResponseViolation);
 
         final Map<String, Object> validatorHeapObject = new LinkedHashMap<>();
@@ -125,7 +131,7 @@ public JsonValue buildRouteJson(final OpenAPI spec, final File specFile,
         if (mockMode) {
             // ----- heap: OpenApiMockResponseHandler entry -----
             final Map<String, Object> mockConfig = new LinkedHashMap<>();
-            mockConfig.put("spec", "${read('" + specFile.getAbsolutePath() + "')}");
+            mockConfig.put("spec", "${read('" + specPath + "')}");
 
             final Map<String, Object> mockHeapObject = new LinkedHashMap<>();
             mockHeapObject.put("name", MOCK_HANDLER_HEAP_NAME);