579e81af82
Adds docs/superpowers/specs/2026-06-30-pluggable-mcp-design.md describing a refactor of main.py: McpService dataclass moves to common/mcp_service.py alongside BUILTIN_SERVICES list and discover_and_filter() helper. Each service package gets a service.py exporting a SERVICE McpService instance. Deployments opt in/out via MCP_SERVICES env whitelist (unset = all). Branch: feat/files-mcp (continues from file-MCP service work; same branch, not pushed; can be split into separate PRs later) Backward compat: 0 existing tools / tests / dependencies changed; unsetting MCP_SERVICES reproduces today's behavior exactly. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>