feat(#1049): phase 5d — drive artifactLayout from the runtime descriptor (retire the 128-LOC switch) (#1053)

resolveRuntimeArtifactLayout now builds Layout from
registry.runtimes[id].runtime.artifactLayout[scope] — a loop dispatching each
ArtifactKind through the SAME 5 builders (commandsKind/agentsKind/skillsKind/
convertedCommandsKind/kimiAgentsKind, unchanged) by (kind, converter, nesting) —
replacing the hardcoded switch(runtime). Equivalence-preserving for all 16 runtimes
× {global, local} (Codex-verified, no divergence). -43 LOC; bin/install.js + the
converters + the install loop untouched. getInstallExports()[converterName]
resolution, configDir threading, scope default, unknown-runtime guard all preserved.

Driving the local scope surfaced a 5a gap: the old switch had no scope branch for 13
runtimes (cursor/gemini/codex/copilot/antigravity/windsurf/augment/trae/qwen/hermes/
codebuddy/opencode/kilo) → local == global for them, but 5a authored local:[].
Backfilled local=global for those 13 (descriptor-faithful; a fall-through shim would
wrongly give cline/kimi local=global). claude/cline/kimi scope-gating untouched.

validateArtifactKindEntry tightened: destSubpath/prefix/nesting/converter required
(ConverterName enum still open — 5e). New 39-case deep-equal golden equivalence test.

Closes #1049

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

capabilities/opencode/capability.json

@@ -31,7 +31,24 @@
           "converter": "convertClaudeCommandToOpencodeSkill"
         }
       ],
-      "local": []
+      "local": [
+        {
+          "kind": "commands",
+          "destSubpath": "command",
+          "prefix": "gsd-",
+          "nesting": "flat",
+          "recursive": false,
+          "converter": null
+        },
+        {
+          "kind": "skills",
+          "destSubpath": "skills",
+          "prefix": "gsd-",
+          "nesting": "flat",
+          "recursive": true,
+          "converter": "convertClaudeCommandToOpencodeSkill"
+        }
+      ]
     },
     "commandStyle": "slash-hyphen",
     "hooksSurface": "none",