Detect active fzf and history-manager Ctrl-R bindings by their configured values, warn with the winning precedence, and let the normal binding options silence the warning.
Pure Nushell sessions do not source hm-session-vars, so feed the same FZF_* values through programs.nushell.environmentVariables before sourcing fzf integration.
Move widget settings under nested option groups while preserving behavior through rename aliases, and centralize FZF environment variable rendering for later reuse.
