Add Policy DSL Validator, Schema Exporter, and Simulation Smoke tools

- Implemented PolicyDslValidator with command-line options for strict mode and JSON output.
- Created PolicySchemaExporter to generate JSON schemas for policy-related models.
- Developed PolicySimulationSmoke tool to validate policy simulations against expected outcomes.
- Added project files and necessary dependencies for each tool.
- Ensured proper error handling and usage instructions across tools.

docs/examples/policies/baseline.stella

@@ -0,0 +1,46 @@
+policy "Baseline Production Policy" syntax "stella-dsl@1" {
+  metadata {
+    description = "Block critical, escalate high, enforce VEX justifications."
+    tags = ["baseline","production"]
+  }
+
+  profile severity {
+    map vendor_weight {
+      source "GHSA" => +0.5
+      source "OSV" => +0.0
+      source "VendorX" => -0.2
+    }
+    env exposure_adjustments {
+      if env.exposure == "internet" then +0.5
+      if env.runtime == "legacy" then +0.3
+    }
+  }
+
+  rule block_critical priority 5 {
+    when severity.normalized >= "Critical"
+    then status := "blocked"
+    because "Critical severity must be remediated before deploy."
+  }
+
+  rule escalate_high_internet {
+    when severity.normalized == "High"
+         and env.exposure == "internet"
+    then escalate to severity_band("Critical")
+    because "High severity on internet-exposed asset escalates to critical."
+  }
+
+  rule require_vex_justification {
+    when vex.any(status in ["not_affected","fixed"])
+         and vex.justification in ["component_not_present","vulnerable_code_not_present"]
+    then status := vex.status
+         annotate winning_statement := vex.latest().statementId
+    because "Respect strong vendor VEX claims."
+  }
+
+  rule alert_warn_eol_runtime priority 1 {
+    when severity.normalized <= "Medium"
+         and sbom.has_tag("runtime:eol")
+    then warn message "Runtime marked as EOL; upgrade recommended."
+    because "Deprecated runtime should be upgraded."
+  }
+}