Add airtable plugin (#1817)

Adds the airtable marketplace entry. Sourced from Airtable/skills at
plugins/airtable, pinned to aaeb4f3e (latest main, tag 2026-05-06).
Bundles the official Airtable MCP server (mcp.airtable.com/mcp) plus
skills for the Airtable data model and filter syntax.

https://claude.ai/code/session_01Vom6RzMA4p6erqGiZxg8yE

Co-authored-by: Claude <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -81,6 +81,22 @@
       },
       "homepage": "https://github.com/AikidoSec/aikido-claude-plugin"
     },
+    {
+      "name": "airtable",
+      "description": "Airtable is the database and operations layer for your agents — whether running product, marketing, sales, ops, HR, or a custom business app. It combines structured data with multiplayer visual surfaces (grid, kanban, calendar, gallery, timeline) humans and agents share — plus sync integrations to Jira, Salesforce, Zendesk, Google Drive, Databricks, and the rest of your stack, all backed by enterprise governance. This plugin makes Claude fluent in Airtable: creating bases and schema, working with records, and sharing UI for collaboration. Bundles the official Airtable MCP server.",
+      "author": {
+        "name": "Airtable"
+      },
+      "category": "productivity",
+      "source": {
+        "source": "git-subdir",
+        "url": "https://github.com/Airtable/skills.git",
+        "path": "plugins/airtable",
+        "ref": "main",
+        "sha": "aaeb4f3ec8d462d694a13fe5c3d249c291bf8899"
+      },
+      "homepage": "https://www.airtable.com"
+    },
     {
       "name": "alloydb",
       "description": "Create, connect, and interact with an AlloyDB for PostgreSQL database and data.",