feat: add PolicyPackSelectorComponent with tests and integration

- Implemented PolicyPackSelectorComponent for selecting policy packs.
- Added unit tests for component behavior, including API success and error handling.
- Introduced monaco-workers type declarations for editor workers.
- Created acceptance tests for guardrails with stubs for AT1–AT10.
- Established SCA Failure Catalogue Fixtures for regression testing.
- Developed plugin determinism harness with stubs for PL1–PL10.
- Added scripts for evidence upload and verification processes.

docs/schemas/acceptance-pack.schema.json

@@ -0,0 +1,30 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Acceptance Pack (Stub)",
+  "description": "Schema stub for AT1–AT10 guardrail pack; to be finalized with signed DSSE envelope.",
+  "type": "object",
+  "properties": {
+    "pack_id": { "type": "string" },
+    "version": { "type": "string" },
+    "inputs_lock": { "type": "string", "description": "Path to pinned versions/seeds." },
+    "signers": {
+      "type": "array",
+      "items": { "type": "string" },
+      "description": "Key IDs that signed the DSSE envelope for this pack"
+    },
+    "fixtures": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "properties": {
+          "id": { "type": "string" },
+          "seed": { "type": "integer" },
+          "expected": { "type": "string" },
+          "artifact": { "type": "string", "description": "Path to fixture artifact" }
+        },
+        "required": ["id", "expected"]
+      }
+    }
+  },
+  "required": ["pack_id", "version", "fixtures"]
+}