feat(azure_policy): test runner, compiler fixes, and example program (#700)

Adds the YAML test runner that exercises the companion test data PRs, plus
several compiler fixes surfaced during testing:

- Removed parameter register caching that produced wrong results inside
  short-circuiting allOf/anyOf blocks; added literal-index caching for
  parameter defaults to avoid repeated O(n) literal-table scans
- Simplified cross-resource effect details to only emit roleDefinitionIds
  and type (deployment templates are not evaluated for compliance)
- Replaced guid/uniqueString builtins with clear "unsupported" errors
- Normalized datetime output to ISO 8601 with Z suffix
- Added azure_policy parser MAX_COL constant (8192) for long template
  expressions, keeping the global DEFAULT_MAX_COL at 1024
- Added rvm to azure_policy feature dependencies since the compiler
  targets RVM bytecode

Also restructures the example binary into examples/regorus/ with new
azure-policy-eval and azure-policy-aliases subcommands, adds C# alias
normalization tests, and documents Azure Policy support in the README.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/azure_policy/cases/parse_errors.yaml

@@ -1,9 +1,10 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 
-# Parse Error Test Suite
-# Tests that malformed policy JSON and invalid constructs are properly rejected.
-# These test cases are expected to fail parsing.
+# Parse Error and Edge Case Test Suite
+# Tests mostly malformed policy JSON and invalid constructs to ensure they are
+# properly rejected, but also includes valid edge cases that verify parser
+# behavior at boundary conditions.
 
 cases:
   # =========================================================================
@@ -267,3 +268,33 @@ cases:
     resource:
       type: "any"
     want_effect: "deny"
+
+  # =========================================================================
+  # Compile errors: unsupported deployment-template functions
+  # =========================================================================
+
+  - note: guid_compile_error
+    policy_rule: |
+      {
+        "if": {
+          "value": "[guid('baseString')]",
+          "equals": "anything"
+        },
+        "then": { "effect": "deny" }
+      }
+    resource:
+      type: "any"
+    want_compile_error: true
+
+  - note: uniquestring_compile_error
+    policy_rule: |
+      {
+        "if": {
+          "value": "[uniqueString('baseString')]",
+          "equals": "anything"
+        },
+        "then": { "effect": "deny" }
+      }
+    resource:
+      type: "any"
+    want_compile_error: true