fix: marketplace.json source fails Claude Code schema validation (#270)

The source field used a bare dot which failed schema validation.
Changed to github source object and added proper plugin.json manifest.

- Added .claude-plugin/plugin.json with skills list and metadata
- Changed marketplace.json source from "." to github repo object
- Removed inline skills array and strict:false from marketplace.json

closes #270

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -13,48 +13,10 @@
     {
       "name": "marketing-skills",
       "description": "38 marketing skills for technical marketers and founders: ASO, CRO, copywriting, cold email, SEO, AI SEO, paid ads, ad creative, churn prevention, pricing strategy, referral programs, revenue operations, sales enablement, customer research, site architecture, and more",
-      "source": ".",
-      "strict": false,
-      "skills": [
-        "skills/ab-test-setup",
-        "skills/ad-creative",
-        "skills/ai-seo",
-        "skills/analytics-tracking",
-        "skills/aso-audit",
-        "skills/churn-prevention",
-        "skills/cold-email",
-        "skills/community-marketing",
-        "skills/competitor-alternatives",
-        "skills/competitor-profiling",
-        "skills/content-strategy",
-        "skills/copy-editing",
-        "skills/copywriting",
-        "skills/customer-research",
-        "skills/directory-submissions",
-        "skills/email-sequence",
-        "skills/form-cro",
-        "skills/free-tool-strategy",
-        "skills/launch-strategy",
-        "skills/lead-magnets",
-        "skills/marketing-ideas",
-        "skills/marketing-psychology",
-        "skills/onboarding-cro",
-        "skills/page-cro",
-        "skills/paid-ads",
-        "skills/paywall-upgrade-cro",
-        "skills/popup-cro",
-        "skills/pricing-strategy",
-        "skills/product-marketing-context",
-        "skills/programmatic-seo",
-        "skills/referral-program",
-        "skills/revops",
-        "skills/sales-enablement",
-        "skills/schema-markup",
-        "skills/seo-audit",
-        "skills/signup-flow-cro",
-        "skills/site-architecture",
-        "skills/social-content"
-      ]
+      "source": {
+        "source": "github",
+        "repo": "coreyhaines31/marketingskills"
+      }
     }
   ]
 }

.claude-plugin/plugin.json

@@ -0,0 +1,51 @@
+{
+  "name": "marketing-skills",
+  "description": "Marketing skills for AI agents — conversion optimization, copywriting, SEO, paid ads, ad creative, and growth",
+  "version": "1.8.0",
+  "author": {
+    "name": "Corey Haines"
+  },
+  "homepage": "https://github.com/coreyhaines31/marketingskills",
+  "repository": "https://github.com/coreyhaines31/marketingskills",
+  "license": "MIT",
+  "skills": [
+    "skills/ab-test-setup",
+    "skills/ad-creative",
+    "skills/ai-seo",
+    "skills/analytics-tracking",
+    "skills/aso-audit",
+    "skills/churn-prevention",
+    "skills/cold-email",
+    "skills/community-marketing",
+    "skills/competitor-alternatives",
+    "skills/competitor-profiling",
+    "skills/content-strategy",
+    "skills/copy-editing",
+    "skills/copywriting",
+    "skills/customer-research",
+    "skills/directory-submissions",
+    "skills/email-sequence",
+    "skills/form-cro",
+    "skills/free-tool-strategy",
+    "skills/launch-strategy",
+    "skills/lead-magnets",
+    "skills/marketing-ideas",
+    "skills/marketing-psychology",
+    "skills/onboarding-cro",
+    "skills/page-cro",
+    "skills/paid-ads",
+    "skills/paywall-upgrade-cro",
+    "skills/popup-cro",
+    "skills/pricing-strategy",
+    "skills/product-marketing-context",
+    "skills/programmatic-seo",
+    "skills/referral-program",
+    "skills/revops",
+    "skills/sales-enablement",
+    "skills/schema-markup",
+    "skills/seo-audit",
+    "skills/signup-flow-cro",
+    "skills/site-architecture",
+    "skills/social-content"
+  ]
+}