feat: expose some cli commands through MCP server

[matt2e]

Changes:

• Refactor child command execution into a shared place so ftl mcp and interactive console can both execute child commands
• MCP declares tools for specific CLI commands that we want exposed
  • Optional args/flags are ignored by default. Can be opted in when adding the command as an MCP tool.
  • args/flags can also be given regex patterns. Refs are automatically given a pattern.
• Remove ftl dump-help as goose no longer needs to be taught about FTL CLI
• Add test to confirm if MCP server can be built from CLI commands (panics if commands or expected options are missing)