fix(#4738): record opencode's staged skills in the install manifest (#4847)

* test(#4738): opencode manifest must record its staged skills (failing first)

* fix(#4738): record opencode's staged skills in the install manifest

* test(#4738): use the centralized temp-dir helper in the manifest tests

* fix(#4738): retire the dead hostBehaviors vocabulary entry, tighten detector asserts, temper changeset

* chore(#4738): backfill changeset PR number (4847)

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Co-authored-by: sim <sim@local>

capabilities/opencode/capability.json

@@ -129,8 +129,7 @@
       },
       "skipHomePrefixSubstitution": true,
       "skipSettingsUi": true,
-      "skipUpdateBannerCommand": true,
-      "skipCodexSkillsManifest": true
+      "skipUpdateBannerCommand": true
     }
   },
   "reviewer": {