feat: Handle computed reference roots in RVM compiler

Allow compile_chained_ref to fall back to “evaluate root expression → chain access”
so literal arrays, comprehensions, and other computed roots no longer raise NotSimpleReferenceChain.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

tests/opa.rs

@@ -32,15 +32,11 @@ const OPA_TODO_FOLDERS: &[&str] = &[
     "example",
     "fix1863",
     "functions",
-    "jsonschema",
     "partialdocconstants",
     "partialobjectdoc",
     "planner-ir",
     "refheads",
-    "replacen",
-    "semverisvalid",
     "sets",
-    "time",
     "type",
     "varreferences",
     "virtualdocs",

tests/rvm/rego/cases/chained_access.yaml

@@ -196,6 +196,30 @@ cases:
     query: data.test.main
     want_result: "web1"
 
+  - note: literal_array_root_access
+    data: {}
+    modules:
+      - |
+        package test
+
+        y := ["x", "y"][1]
+
+        main := y
+    query: data.test.main
+    want_result: "y"
+
+  - note: computed_object_root_access
+    data: {}
+    modules:
+      - |
+        package test
+
+        x := strings.replace_n({k: v | k := ["f", "foo"][i]; v := ["x", "xxx"][i]}, "foo")
+
+        main := x
+    query: data.test.main
+    want_result: "xoo"
+
   - note: string_literal_bracket_access
     data: {}
     modules: