Add signal contracts for reachability, exploitability, trust, and unknown symbols

- Introduced `ReachabilityState`, `RuntimeHit`, `ExploitabilitySignal`, `ReachabilitySignal`, `SignalEnvelope`, `SignalType`, `TrustSignal`, and `UnknownSymbolSignal` records to define various signal types and their properties.
- Implemented JSON serialization attributes for proper data interchange.
- Created project files for the new signal contracts library and corresponding test projects.
- Added deterministic test fixtures for micro-interaction testing.
- Included cryptographic keys for secure operations with cosign.

docs/notifications/schemas/inputs.lock

@@ -3,12 +3,12 @@
   "hash_algorithm": "blake3-256",
   "canonicalization": "json-normalized-utf8",
   "entries": [
-    { "file": "event-envelope.schema.json", "digest": "TBD" },
-    { "file": "rule.schema.json", "digest": "TBD" },
-    { "file": "template.schema.json", "digest": "TBD" },
-    { "file": "channel.schema.json", "digest": "TBD" },
-    { "file": "receipt.schema.json", "digest": "TBD" },
-    { "file": "webhook.schema.json", "digest": "TBD" },
-    { "file": "dlq-notify.schema.json", "digest": "TBD" }
+    { "file": "event-envelope.schema.json", "digest": "0534e778a7e24dfdcbdc66cec2902f24684ec0bdf26d708ab9bca98e6674a318" },
+    { "file": "rule.schema.json", "digest": "34d4f1c2ba97b76acf85ad61f4e8de4591664eefecbc7ebb6d168aa5a998ddd1" },
+    { "file": "template.schema.json", "digest": "e0a8f9bb5e5f29a11b040e7cb0e7e9a8c5d42256f9a4bd72f79460eb613dac52" },
+    { "file": "channel.schema.json", "digest": "bd9e2dfb4e6e7e7a38f26cc94ae8bcdf9b8c44b1e97bf78c146711783fe8fa2b" },
+    { "file": "receipt.schema.json", "digest": "fb4431019b3803081983b215fc9ca2e7618c3cf91f8274baedf72cacad8dfe46" },
+    { "file": "webhook.schema.json", "digest": "54a6e0d956fd6af7e88f6508bda78221ca04cfedea4112bfefc7fa5dbfa45c09" },
+    { "file": "dlq-notify.schema.json", "digest": "1330e589245b923f6e1fea6af080b7b302a97effa360a90dbef4ba3b06021b2f" }
   ]
 }

docs/notifications/schemas/notify-schemas-catalog.dsse.json

@@ -1,6 +1,11 @@
 {
   "payloadType": "application/vnd.notify.schema-catalog+json",
-  "payload": "BASE64_ENCODED_NOTIFY_SCHEMA_CATALOG_TBD",
-  "signatures": [],
-  "note": "Placeholder; replace with signed payload once BLAKE3 digest and signing key are available."
+  "payload": "eyJjYW5vbmljYWxpemF0aW9uIjoianNvbi1ub3JtYWxpemVkLXV0ZjgiLCJjYXRhbG9nX3ZlcnNpb24iOiJ2MS4wIiwiZ2VuZXJhdGVkX2F0IjoiMjAyNS0xMi0wNFQwMDowMDowMFoiLCJoYXNoX2FsZ29yaXRobSI6ImJsYWtlMy0yNTYiLCJzY2hlbWFzIjpbeyJkaWdlc3QiOiIwNTM0ZTc3OGE3ZTI0ZGZkY2JkYzY2Y2VjMjkwMmYyNDY4NGVjMGJkZjI2ZDcwOGFiOWJjYTk4ZTY2NzRhMzE4IiwiZmlsZSI6ImV2ZW50LWVudmVsb3BlLnNjaGVtYS5qc29uIiwiaWQiOiJldmVudC1lbnZlbG9wZSIsInZlcnNpb24iOiJ2MS4wIn0seyJkaWdlc3QiOiIzNGQ0ZjFjMmJhOTdiNzZhY2Y4NWFkNjFmNGU4ZGU0NTkxNjY0ZWVmZWNiYzdlYmI2ZDE2OGFhNWE5OThkZGQxIiwiZmlsZSI6InJ1bGUuc2NoZW1hLmpzb24iLCJpZCI6InJ1bGUiLCJ2ZXJzaW9uIjoidjEuMCJ9LHsiZGlnZXN0IjoiZTBhOGY5YmI1ZTVmMjlhMTFiMDQwZTdjYjBlN2U5YThjNWQ0MjI1NmY5YTRiZDcyZjc5NDYwZWI2MTNkYWM1MiIsImZpbGUiOiJ0ZW1wbGF0ZS5zY2hlbWEuanNvbiIsImlkIjoidGVtcGxhdGUiLCJ2ZXJzaW9uIjoidjEuMCJ9LHsiZGlnZXN0IjoiYmQ5ZTJkZmI0ZTZlN2U3YTM4ZjI2Y2M5NGFlOGJjZGY5YjhjNDRiMWU5N2JmNzhjMTQ2NzExNzgzZmU4ZmEyYiIsImZpbGUiOiJjaGFubmVsLnNjaGVtYS5qc29uIiwiaWQiOiJjaGFubmVsIiwidmVyc2lvbiI6InYxLjAifSx7ImRpZ2VzdCI6ImZiNDQzMTAxOWIzODAzMDgxOTgzYjIxNWZjOWNhMmU3NjE4YzNjZjkxZjgyNzRiYWVkZjcyY2FjYWQ4ZGZlNDYiLCJmaWxlIjoicmVjZWlwdC5zY2hlbWEuanNvbiIsImlkIjoicmVjZWlwdCIsInZlcnNpb24iOiJ2MS4wIn0seyJkaWdlc3QiOiI1NGE2ZTBkOTU2ZmQ2YWY3ZTg4ZjY1MDhiZGE3ODIyMWNhMDRjZmVkZWE0MTEyYmZlZmM3ZmE1ZGJmYTQ1YzA5IiwiZmlsZSI6IndlYmhvb2suc2NoZW1hLmpzb24iLCJpZCI6IndlYmhvb2siLCJ2ZXJzaW9uIjoidjEuMCJ9LHsiZGlnZXN0IjoiMTMzMGU1ODkyNDViOTIzZjZlMWZlYTZhZjA4MGI3YjMwMmE5N2VmZmEzNjBhOTBkYmVmNGJhM2IwNjAyMWIyZiIsImZpbGUiOiJkbHEtbm90aWZ5LnNjaGVtYS5qc29uIiwiaWQiOiJkbHEiLCJ2ZXJzaW9uIjoidjEuMCJ9XX0=",
+  "signatures": [
+    {
+      "sig": "99WPzzc6sCaEQHXk2B15aLxtG/Ics6qsgHYa2oDTI1g=",
+      "keyid": "notify-dev-hmac-001",
+      "signedAt": "2025-12-04T21:12:53+00:00"
+    }
+  ]
 }

docs/notifications/schemas/notify-schemas-catalog.json

@@ -4,12 +4,12 @@
   "canonicalization": "json-normalized-utf8",
   "generated_at": "2025-12-04T00:00:00Z",
   "schemas": [
-    { "id": "event-envelope", "file": "event-envelope.schema.json", "version": "v1.0", "digest": "TBD" },
-    { "id": "rule", "file": "rule.schema.json", "version": "v1.0", "digest": "TBD" },
-    { "id": "template", "file": "template.schema.json", "version": "v1.0", "digest": "TBD" },
-    { "id": "channel", "file": "channel.schema.json", "version": "v1.0", "digest": "TBD" },
-    { "id": "receipt", "file": "receipt.schema.json", "version": "v1.0", "digest": "TBD" },
-    { "id": "webhook", "file": "webhook.schema.json", "version": "v1.0", "digest": "TBD" },
-    { "id": "dlq", "file": "dlq-notify.schema.json", "version": "v1.0", "digest": "TBD" }
+    { "id": "event-envelope", "file": "event-envelope.schema.json", "version": "v1.0", "digest": "0534e778a7e24dfdcbdc66cec2902f24684ec0bdf26d708ab9bca98e6674a318" },
+    { "id": "rule", "file": "rule.schema.json", "version": "v1.0", "digest": "34d4f1c2ba97b76acf85ad61f4e8de4591664eefecbc7ebb6d168aa5a998ddd1" },
+    { "id": "template", "file": "template.schema.json", "version": "v1.0", "digest": "e0a8f9bb5e5f29a11b040e7cb0e7e9a8c5d42256f9a4bd72f79460eb613dac52" },
+    { "id": "channel", "file": "channel.schema.json", "version": "v1.0", "digest": "bd9e2dfb4e6e7e7a38f26cc94ae8bcdf9b8c44b1e97bf78c146711783fe8fa2b" },
+    { "id": "receipt", "file": "receipt.schema.json", "version": "v1.0", "digest": "fb4431019b3803081983b215fc9ca2e7618c3cf91f8274baedf72cacad8dfe46" },
+    { "id": "webhook", "file": "webhook.schema.json", "version": "v1.0", "digest": "54a6e0d956fd6af7e88f6508bda78221ca04cfedea4112bfefc7fa5dbfa45c09" },
+    { "id": "dlq", "file": "dlq-notify.schema.json", "version": "v1.0", "digest": "1330e589245b923f6e1fea6af080b7b302a97effa360a90dbef4ba3b06021b2f" }
   ]
 }