feat(identity): trust site-provided IMDb/TMDB IDs in scoring (ID-3)

MatchOptions.trustedIds: a candidate fetched by a site-given ID is at least
multi_evidence even when titles differ; year/type conflicts stay candidates.
Differential group site-ids-* against MP search/result.py _match_source.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/domain/test/differential/identity/site-ids-mp.json

@@ -0,0 +1,27 @@
+{
+  "generatedFrom": {
+    "repo": "MoviePilot",
+    "commit": "e6820a8",
+    "entry": "app.chain.search.result._match_source"
+  },
+  "results": {
+    "S-001": {
+      "match": "imdb"
+    },
+    "S-002": {
+      "match": "imdb"
+    },
+    "S-003": {
+      "match": "imdb"
+    },
+    "S-004": {
+      "match": "imdb"
+    },
+    "S-005": {
+      "match": "imdb"
+    },
+    "S-006": {
+      "match": "imdb"
+    }
+  }
+}