Add sample proof bundle configurations and verification script

- Introduced sample proof bundle configuration files for testing, including `sample-proof-bundle-config.dsse.json`, `sample-proof-bundle.dsse.json`, and `sample-proof-bundle.json`.
- Implemented a verification script `test_verify_sample.sh` to validate proof bundles against specified schemas and catalogs.
- Updated existing proof bundle configurations with new metadata, including versioning, created timestamps, and justification details.
- Enhanced evidence entries with expiration dates and hashes for better integrity checks.
- Ensured all new configurations adhere to the defined schema for consistency and reliability in testing.

docs/modules/evidence-locker/schemas/checksums.schema.json

@@ -0,0 +1,47 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://stellaops.local/schemas/evidence/checksums.schema.json",
+  "title": "StellaOps Evidence Bundle Checksums (EB2)",
+  "description": "Canonical checksum map used to derive the Merkle root and DSSE subject for evidence bundles.",
+  "type": "object",
+  "additionalProperties": false,
+  "required": ["algorithm", "root", "entries"],
+  "properties": {
+    "algorithm": { "type": "string", "enum": ["sha256"] },
+    "root": { "type": "string", "pattern": "^[0-9a-f]{64}$" },
+    "generatedAt": { "type": "string", "format": "date-time" },
+    "bundleId": { "type": "string", "pattern": "^[0-9a-fA-F]{32}$" },
+    "tenantId": { "type": "string", "pattern": "^[0-9a-fA-F]{32}$" },
+    "entries": {
+      "type": "array",
+      "minItems": 1,
+      "description": "Sorted list of entry hashes; order must be lexicographic on canonicalPath.",
+      "items": { "$ref": "#/$defs/checksumEntry" }
+    },
+    "chunking": {
+      "type": "object",
+      "description": "Optional chunked/CAS hashing strategy for large payloads.",
+      "additionalProperties": false,
+      "properties": {
+        "strategy": { "type": "string", "enum": ["none", "fixed", "buzhash"] },
+        "chunkSizeBytes": { "type": "integer", "minimum": 1024 },
+        "casDigestAlgorithm": { "type": "string", "enum": ["sha256"] }
+      }
+    }
+  },
+  "$defs": {
+    "checksumEntry": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["canonicalPath", "sha256", "sizeBytes"],
+      "properties": {
+        "canonicalPath": {
+          "type": "string",
+          "pattern": "^(?:[A-Za-z0-9_.-]+/)*[A-Za-z0-9_.-]+$"
+        },
+        "sha256": { "type": "string", "pattern": "^[0-9a-f]{64}$" },
+        "sizeBytes": { "type": "integer", "minimum": 0 }
+      }
+    }
+  }
+}