Right-click context menu on panes with move/layout actions (and plugin action integration)

[osamahbeig]

Problem

Layout operations — moving a pane to another tab or workspace, changing a split from stacked to side-by-side, swapping two panes — are inherently mouse-shaped: you're pointing at a thing and saying "put it over there." Today they're only reachable through keybindings and the CLI. Panes have no context menu at all, and the existing tab/workspace menus only cover rename/close.

Two gaps compound this:

1. No in-place re-split. Converting a stacked pair to side-by-side requires bouncing the pane out (pane move --new-tab) and moving it back with the other --split direction. Works, but nobody discovers it.
2. Plugins can't help. Plugin v1 has no native-UI extension point, so the best a plugin can offer is a keybinding-launched overlay pane that takes over the screen — a keyboard-person workaround for what should be two clicks.

Proposal

Right-click on a pane (body or border) opens a context menu with layout actions:

• Move to tab… (submenu: tabs across workspaces)
• Move to workspace… / Move to new tab / new workspace
• Re-split → right / down (doing the temp-tab bounce internally)
• Swap with ← → ↑ ↓
• Close

Extensibility (optional but high-leverage)

Surface installed plugin actions in the same menu when their manifest contexts matches the click target (pane, tab, workspace). That would give plugin v1 a real UI hook without designing a full native-UI API — the contexts field already exists in the manifest and seems built for exactly this.

Alternatives considered

I built the overlay-pane plugin version of this: herdr-pane-mover (keybinding → full-screen clickable menu → move executes, four-direction placement). It works, but the UX gap vs. a native right-click menu is exactly why I'm requesting this upstream. Happy to share the plugin or contribute toward the native version if useful.

[Blue-B]

Also very interested in this. Mouse-based pane management is the main thing I miss: moving a pane to another workspace or tab, re-splitting, swapping two panes, and starting an agent in an existing pane. The current keyboard/CLI-only flow is painful when juggling several agent panes. Happy to test as soon as a preview includes it.

[airtonix]

related #2391