fix(ticket): project immutable results and typed source observations

T-716: merged evidence uses recorded result approval; open source reads use Runtime provider authority and preserve unavailability. Current requirements use the shared exact snapshot evaluator. Remove primary-MR/report SQL heuristics; continue bounded query scans through nonmatching candidates. Align Worker/Web projections and explain lifecycle versus integration/attestation. Synchronize checker test on delivered inputs, not pre-delivery attempt state.

Validation: root cargo check; cargo test -p merge-request (30), -p server-api (70), -p worker (949), -p yoi-workspace-server (620 lib + 11 binary); server-api typescript feature check; 32 focused Deno tests; deno task check (0 errors/warnings); cargo fmt --all -- --check; git diff --check HEAD; canonical OpenAPI/generated Ticket artifact checks.

openapi/server-api.json

@@ -11221,6 +11221,12 @@
               "null"
             ]
           },
+          "integration_evidence_error": {
+            "type": [
+              "string",
+              "null"
+            ]
+          },
           "merge_request_id": {
             "type": "string"
           },
@@ -11263,6 +11269,9 @@
           "selector_to": {
             "type": "string"
           },
+          "source_ref_observation": {
+            "$ref": "#/components/schemas/TicketSourceRefObservation"
+          },
           "state": {
             "type": "string"
           },
@@ -11276,7 +11285,8 @@
           "state",
           "review_status",
           "selector_to",
-          "updated_at"
+          "updated_at",
+          "source_ref_observation"
         ],
         "type": "object"
       },
@@ -12069,6 +12079,53 @@
         },
         "type": "object"
       },
+      "TicketSourceRefObservation": {
+        "oneOf": [
+          {
+            "additionalProperties": false,
+            "properties": {
+              "status": {
+                "const": "observed",
+                "type": "string"
+              }
+            },
+            "required": [
+              "status"
+            ],
+            "type": "object"
+          },
+          {
+            "additionalProperties": false,
+            "properties": {
+              "code": {
+                "type": "string"
+              },
+              "status": {
+                "const": "unavailable",
+                "type": "string"
+              }
+            },
+            "required": [
+              "status",
+              "code"
+            ],
+            "type": "object"
+          },
+          {
+            "additionalProperties": false,
+            "properties": {
+              "status": {
+                "const": "not_required",
+                "type": "string"
+              }
+            },
+            "required": [
+              "status"
+            ],
+            "type": "object"
+          }
+        ]
+      },
       "TicketStateChange": {
         "properties": {
           "author": {
@@ -15481,7 +15538,7 @@
   "info": {
     "title": "Yoi Server API",
     "version": "0.1.0",
-    "x-yoi-source-digest": "sha256:a6a7147c9a2f465a5da044e9ba21947cb3d86eacbfe3905696483917e794d5cf"
+    "x-yoi-source-digest": "sha256:4f468e00efa86e6e33e8fa4f14deca93ee15b955071920facd56c59c3d2fefb8"
   },
   "openapi": "3.1.0",
   "paths": {