Add support for ГОСТ Р 34.10 digital signatures

- Implemented the GostKeyValue class for handling public key parameters in ГОСТ Р 34.10 digital signatures.
- Created the GostSignedXml class to manage XML signatures using ГОСТ 34.10, including methods for computing and checking signatures.
- Developed the GostSignedXmlImpl class to encapsulate the signature computation logic and public key retrieval.
- Added specific key value classes for ГОСТ Р 34.10-2001, ГОСТ Р 34.10-2012/256, and ГОСТ Р 34.10-2012/512 to support different signature algorithms.
- Ensured compatibility with existing XML signature standards while integrating ГОСТ cryptography.

docs/vex/consensus-json.md

@@ -11,6 +11,18 @@
       "status": "NOT_AFFECTED",
       "justification": "component_not_present",
       "weight": 0.62,
+      "trust": {
+        "tier": "distro",
+        "note": "tier=distro;weight=0.62",
+        "weight": 0.62,
+        "cosign": {
+          "issuer": "https://issuer.redhat.com",
+          "identityPattern": "spiffe://redhat/vex/*"
+        },
+        "pgpFingerprints": [
+          "04F2C0A87B1D9E90B1D8A35DCEB5ABCD12345678"
+        ]
+      },
       "lastObserved": "2025-11-04T18:22:31Z",
       "accepted": true,
       "reason": "trust-tier vendor, signed OpenVEX"
@@ -20,6 +32,11 @@
       "status": "AFFECTED",
       "justification": null,
       "weight": 0.27,
+      "trust": {
+        "tier": "community",
+        "note": "tier=community;weight=0.27",
+        "weight": 0.27
+      },
       "lastObserved": "2025-11-05T01:12:03Z",
       "accepted": false,
       "reason": "lower trust tier and stale statement"
@@ -32,3 +49,4 @@
 ```
 
 > **Note:** This payload is generated from the beta consensus endpoint and is subject to change prior to GA. Keys and semantics are documented alongside API previews in `docs/modules/excitor/README.md`.
+> **New:** `sources[].trust` mirrors the `vex.provenance.*` envelope emitted by Excititor connectors (provider weight/tier, cosign hints, PGP fingerprints). VEX Lens copies the raw metadata so Policy Engine, Console, and Advisory AI can explain consensus decisions without replaying ingestion.