Add safe project display labels

[Cheol-H-Jeong]

Summary

• add optional project display labels without changing stable project names or cwd paths
• show friendly labels with real folder context in tmux windows, sidebars, and status overlay
• keep sidebar/click/resume behavior keyed by stable project identity
• dim stale unsearchable status command rows and prevent dead jump clicks
• fix agent running/done sidebar status semantics for GJC activity detection

Verification

• node -c bin/nmux-linux && node -c bin/nmux-linux-sidebar && node --test test/*.test.js
• npm run check