fix: shorten server.json description to fit MCP Registry 100-char limit

Previous description was 125 chars, MCP Registry rejects > 100.
Also adds GOOGLE_MAPS_ENABLED_TOOLS env var declaration.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: cablate

server.json

@@ -2,7 +2,7 @@
   "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
   "name": "io.github.cablate/google-map",
   "title": "Google Maps MCP Server",
-  "description": "Google Maps tools for AI agents — geocode, search, directions, elevation. stdio + HTTP.",
+  "description": "17 Google Maps tools for AI agents — geocode, search, directions, weather, air quality, and more.",
   "repository": {
     "url": "https://github.com/cablate/mcp-google-map",
     "source": "github"
@@ -23,6 +23,13 @@
           "isRequired": true,
           "format": "string",
           "isSecret": true
+        },
+        {
+          "name": "GOOGLE_MAPS_ENABLED_TOOLS",
+          "description": "Comma-separated tool names to enable. Omit or * for all 17 tools.",
+          "isRequired": false,
+          "format": "string",
+          "isSecret": false
         }
       ]
     }