fix(hosts): delete five dead HostConfig fields

metadataFormat (generator hardcodes openai.yaml), sidecar (behavior lives in
setup's create_agents_sidecar — knowledge preserved as a comment in codex.ts),
install.prefixable (skill_prefix is implemented entirely in bin/gstack-config),
staticFiles (docstring cited a SOUL.md that never existed anywhere), and
adapter (its only would-be consumer, openclaw-adapter.ts, was fully dead —
with a test asserting the field was undefined). Kept: learningsMode (wired
next), linkingStrategy (validation reads it), coAuthorTrailer (consumed by
resolvers/utility.ts).

Proof: JSON dump diff shows ONLY the deleted keys vanishing; zero-diff regen
across all 10 hosts; host-config + gen-skill-docs suites green. Note: this
commit also carries chunk-23 edits to the shared hosts/claude.ts +
define-host.ts + host-config.test.ts files (skipSkills collapse, stale
line-number comment drops) — pathspec commits, concurrent prep.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

hosts/claude.ts

@@ -14,14 +14,13 @@ const claude = defineHost({
 
   generation: {
     generateMetadata: false,
-    skipSkills: ['claude'],  // Claude outside-voice skill is for non-Claude hosts
+    skipSkills: [],  // overrides the default ['codex'] — the /codex skill IS a Claude skill (wrapper around codex exec)
   },
 
   pathRewrites: [],  // Claude is the primary host — no rewrites needed
   toolRewrites: {},
 
   install: {
-    prefixable: true,
     linkingStrategy: 'real-dir-symlink',
   },