Settings › Appearance › Layout brings back the three panels as an option beside the grid

[davidbudac]

Brings back the PROJECTS | WORKTREES | SESSIONS columns from before 0.34 as an opt-in layout. Settings › Appearance › Layout gets panels next to grid, and grid stays the default. This addresses #108 and supersedes #122, which I closed to rework it into this smaller, reviewable series.

Contents: 📸 Screenshots · ✨ What you get · 🧭 What changes for grid users · ⚠️ Risk · 🔧 Technical overview

📸 Screenshots

The three columns beside the pane	Inline follow-up on a session

✨ What you get

• A Layout setting: grid (default) or panels
  • layout in config.json; the setting switches live, no restart
  • the selected project, worktree and session, and the attached pane, carry across the switch
• The columns, built on the grid's own state
  • same cursors the grid already uses, so there is no second selection model
  • the old row shapes, colours, ? help and keys (⇧Tab / ^⇧H / ^⇧L walk, z full screen, m row menu)
  • Space opens the inline follow-up box on a session; recent prompts show under each one
• Columns you can shape
  • drag a border to resize; widths are saved in the UI state and survive a restart
  • ⇧P / ⇧B / ⇧S fold a column to a rail; a window too narrow for the saved widths shrinks them proportionally
• What stayed the same: the grid's drawing and key bindings. Apart from the fixes in the next section, grid users only see the new rows in Settings › Appearance.

🧭 What changes for grid users

One commit (The pane only takes input when it shows a live session…) changes shared code. The panels needed these fixes, and the same holes exist in the grid:

• A PR, issue or cloud reader covering a still-attached session no longer passes keystrokes, paste or mouse reports to the hidden PTY. PgUp/PgDn/Home/End scroll the reader.
• Attaching an archived agent shows a flash and does not attach.
• Full screen with no terminal in the pane refuses with a message, and the key-combo echo no longer says "Full screen" when it didn't happen.

The commit is self-contained, so I can split it into its own PR if you prefer.

⚠️ Risk

Verdict: 🟢 Low. Everything new is behind layout = panels, and the shared changes only make the pane refuse input in more cases.

	Level	Why
🔒 Security & production	Low	No new surface: no new ClientRequest, daemon code or protocol change. Two additive config/UI-state keys (layout, panels_widths); older files read as before.
⚡ Performance	Low	The grid's draw path is unchanged. The panels code runs only with layout = panels.
🧩 Fit	Low	Three new modules mirroring the launcher's split (panels.rs model, event_loop/panels.rs keys, ui/panels_view.rs draw). Shared files get panels_active() branches and the input gate above.

Rollback: git revert the merge removes everything. Saved layout / panels_widths keys are then ignored, and the hide_* / recent_prompts* settings return to being retired-but-preserved.

🔧 Technical overview

Commits, files, tests

Size: about 6,300 added lines, of which roughly 2,500 are tests and 400 are docs and screenshot scenes.

Five commits, each builds on its own:

1. Layout setting and the three columns, with help and wheel scrolling
2. Drag-to-resize borders, with persisted widths
3. Old row shapes, folding columns, panel keys, inline follow-up
4. Pane input gate (shared, see above)
5. Screenshot scenes (make shot SCENE=panels…, plus RESTART=1 in shot.sh for the restart scene)

Where to start reading: crates/nebula-tui/src/panels.rs has the layout maths (columns()) and the row model. event_loop/panels.rs routes keys and mouse ahead of the grid's keymap only when app.panels_active(). In app.rs, pane_shows_terminal / pane_accepts_input are the shared gate.

flowchart LR
  CFG["config: layout"] --> APP["App.panels"]
  APP -->|grid| GRID["grid: launcher, ui.rs"]
  APP -->|panels| EV["event_loop/panels.rs"]
  EV --> MODEL["panels.rs: columns(), rows"]
  MODEL --> VIEW["ui/panels_view.rs"]
  EV --> GATE["App::pane_accepts_input"]
  GRID --> GATE
  GATE --> PTY["PTY input"]
  classDef changed fill:#fde68a,stroke:#b45309,color:#111
  class EV,MODEL,VIEW,GATE changed

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Not done: workspaces. They were removed alongside the old panels, but this PR is only the layout.

Gate: cargo fmt --check is clean. cargo clippy adds no warnings; the 11 it reports also appear on main with a current toolchain. cargo test --workspace: 1772 passed, 4 failed. The same 4 fail on main on my machine (Linux): question_mark_ignores_menus_without_session_rows, the_harness_picker_is_no_wider_than_its_rows_and_keeps_its_keys_in_the_footer, nebula_open_from_inside_a_session_raises_the_file_tabs and tui_drag_past_the_pane_top_autoscrolls_and_copies_the_run. A few branch_switch / ipc tests also fail intermittently here; this PR doesn't touch those files. New coverage: ~75 unit tests (layout maths, drag floors, folds, persistence, follow-up, the input gate in both layouts) and 2 e2e tests (switching the layout live, and walking the columns).

Closes #108

🤖 Generated with Claude Code

[davidbudac]

Hi Cody, this took surprisingly long and a lot of effort. I was aiming for a simple switch in the settings which I think I achieved.