Save and restore named workspace sessions (tmux-resurrect style)

[dukeeagle]

Feature request

Support saving the current set of open workspaces as a named session, and restoring it later, much like tmux-resurrect but for cmux workspace layouts.

Motivation

I frequently have 4-6 workspaces open for a project context (monorepo services, infra, docs, etc). When I need to context-switch to a different project, I close everything and manually reopen. Being able to save/restore named sessions would make this instant.

Current session restore only covers the most recent state on relaunch — there's no way to go back to a previous workspace configuration or switch between saved setups.

Suggested UX

cmux session save my-project
cmux session restore my-project
cmux session list
cmux session delete my-project

Each session would capture workspace count/order, working directories, and pane layout.

Related issues

• App sometimes launches to a frozen blank state — sidebar empty, terminal not loaded #399 — session restore race on launch
• cmux settings/tabs lost after macOS system update #2072 — settings/tabs lost after macOS update (named session backups would also help here)
• Persistence of tab information and pane layouts #480 — persistence of tab information and pane layouts