fix: Remove orphaned MERIDIAN_API_KEY from develop env template

No longer consumed after mcp-server-develop container removal.

Author: bjcoombs

deploy/develop/.env.develop.template

@@ -126,9 +126,6 @@ JWT_SIGNING_ISSUER=meridian-develop
 # [REQUIRED] Public base URL for MCP OAuth callbacks.
 MCP_BASE_URL=https://develop.meridianhub.cloud
 
-# [REQUIRED] API key for service-to-service auth.
-MERIDIAN_API_KEY=
-
 # [OPTIONAL] Enable OAuth 2.1 for MCP clients.
 MCP_OAUTH_ENABLED=true