chore(config): superpowers citers by bare name, routing map, docs, settings

Every superpowers-prefixed skill call in ship-feature, init-project, tour,
deploy, audit-delta, plugin-advisor and lib/analyze-before-plan now names
the vendored skill directly. finishing-a-development-branch is described
as the upstream skill this config does not vendor (gitflow finish is the
integration path). CLAUDE.global.md Skill routing maps the four
non-vendored skills the vendored text still references. settings.json
loses the plugin key and its marketplace block; README, USAGE,
plugin-advisor and the profile skill describe superpowers as vendored
skills, always on, zero plugin cost. CHANGELOG entry with a known
residual.

settings.json

@@ -420,7 +420,6 @@
     "example-skills@anthropic-agent-skills": false,
     "ui-ux-pro-max@ui-ux-pro-max-skill": true,
     "security-guidance@claude-code-plugins": true,
-    "superpowers@superpowers-marketplace": true,
     "pr-review-toolkit@claude-code-plugins": false,
     "brightdata-plugin@synced": false
   },
@@ -431,12 +430,6 @@
         "repo": "anthropics/claude-code"
       }
     },
-    "superpowers-marketplace": {
-      "source": {
-        "source": "github",
-        "repo": "obra/superpowers-marketplace"
-      }
-    },
     "ui-ux-pro-max-skill": {
       "source": {
         "source": "github",