feat: Soft-assert mode for builtin out-params under not

- Add a scoped soft_assert_mode to the compiler so `not` statements compile their subexpressions without emitting hard AssertCondition/AssertNotUndefined instructions.
- Teach binding-plan application to return an optional result register; equality plans now yield a boolean in soft mode, allowing not abs(-5 , 3) to succeed instead of aborting.
- Update function-call, loop, and rule plumbing to consume the new binding-plan outcome, including copying the produced register when an out-parameter equality is used.
- Trim the OPA TODO list to the remaining troublesome folders.

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

tests/rvm/rego/cases/builtins_out_params.yaml

@@ -81,3 +81,15 @@ cases:
         }
     query: data.test.rule5
     want_result: "#undefined"
+
+  - note: builtin_out_param_negated_equality
+    data: {}
+    modules:
+      - |
+        package test
+
+        rule5 if {
+            not abs(-5, 3)
+        }
+    query: data.test.rule5
+    want_result: true