fix: shorten server.json description to fit MCP Registry 100-char limit (#54)

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": "17 Google Maps tools for AI agents — geocode, search, directions, weather, air quality, map images, and more. 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"
@@ -26,7 +26,7 @@
         },
         {
           "name": "GOOGLE_MAPS_ENABLED_TOOLS",
-          "description": "Comma-separated list of tool names to enable (e.g. maps_geocode,maps_directions). Omit or set to * for all 17 tools.",
+          "description": "Comma-separated tool names to enable. Omit or * for all 17 tools.",
           "isRequired": false,
           "format": "string",
           "isSecret": false