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/task-packs/approvals-ledger.schema.json

@@ -0,0 +1,48 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "StellaOps Task Pack Approval Ledger",
+  "description": "DSSE payload recording approval decisions for Task Pack gates.",
+  "type": "object",
+  "additionalProperties": false,
+  "required": [
+    "schemaVersion",
+    "runId",
+    "gateId",
+    "planHash",
+    "decision",
+    "decidedAt",
+    "tenantId",
+    "approver"
+  ],
+  "properties": {
+    "schemaVersion": {
+      "type": "string",
+      "const": "stellaops.pack.approval-ledger.v1"
+    },
+    "runId": { "type": "string", "minLength": 1 },
+    "gateId": { "type": "string", "minLength": 1 },
+    "planHash": { "type": "string", "pattern": "^sha256:[0-9a-f]{64}$" },
+    "decision": { "type": "string", "enum": ["approved", "rejected", "expired"] },
+    "decidedAt": { "type": "string", "format": "date-time" },
+    "tenantId": { "type": "string", "minLength": 1 },
+    "environment": { "type": "string" },
+    "approver": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["id"],
+      "properties": {
+        "id": { "type": "string", "minLength": 1 },
+        "summary": { "type": "string" }
+      }
+    },
+    "reason": { "type": "string" },
+    "evidence": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "requestDigest": { "type": "string", "pattern": "^sha256:[0-9a-f]{64}$" },
+        "responseDigest": { "type": "string", "pattern": "^sha256:[0-9a-f]{64}$" }
+      }
+    }
+  }
+}