fix: add COCKROACHDB_SSLMODE env var to mcp.json for parity with claude-plugin

The cockroachdb-toolbox backend was missing the COCKROACHDB_SSLMODE
environment variable passthrough, which prevents users from configuring
SSL modes (disable, require, verify-full) when connecting to CockroachDB.

Author: viragtripathi

mcp.json

@@ -8,7 +8,8 @@
         "COCKROACHDB_PORT": "${COCKROACHDB_PORT}",
         "COCKROACHDB_USER": "${COCKROACHDB_USER}",
         "COCKROACHDB_PASSWORD": "${COCKROACHDB_PASSWORD}",
-        "COCKROACHDB_DATABASE": "${COCKROACHDB_DATABASE}"
+        "COCKROACHDB_DATABASE": "${COCKROACHDB_DATABASE}",
+        "COCKROACHDB_SSLMODE": "${COCKROACHDB_SSLMODE}"
       }
     },
     "cockroachdb-toolbox-http": {