feat: add TUI session orchestrator

Add a first-class active-session orchestrator for the Ink TUI:

- list, activate, close, and launch live process-local TUI sessions
- hydrate committed and in-flight output when switching sessions
- dispatch a new prompt session from the +new row with session-scoped model picks
- expose a clickable live-session count in the status chrome
- preserve stable row order while initially focusing the current session
- support mouse hit-testing for floating orchestrator overlays
- add backend and frontend regression coverage for the lifecycle and UI helpers

website/docs/user-guide/tui.md

@@ -89,7 +89,7 @@ Keybindings match the [Classic CLI](cli.md#keybindings) exactly. The only behavi
 - **`Cmd+V` / `Ctrl+V`** first tries normal text paste, then falls back to OSC52/native clipboard reads, and finally image attach when the clipboard or pasted payload resolves to an image.
 - **`/terminal-setup`** installs local VS Code / Cursor / Windsurf terminal bindings for better `Cmd+Enter` and undo/redo parity on macOS.
 - **Slash autocompletion** opens as a floating panel with descriptions, not an inline dropdown.
-- **`Ctrl+X`** — when a queued message is highlighted (sent while the agent was still running), delete it from the queue. **`Esc`** cancels editing and unhighlights without deleting.
+- **`Ctrl+X`** opens the live session switcher. When a queued message is highlighted (sent while the agent was still running), it still deletes that queued message instead. **`Esc`** cancels editing and unhighlights without deleting.
 - **`Ctrl+G` / `Ctrl+X Ctrl+E`** — open the current input buffer in `$EDITOR` for multi-line / long-prompt composition; save-and-exit sends the contents back as the prompt.
 
 ## Slash commands
@@ -99,7 +99,7 @@ All slash commands work unchanged. A few are TUI-owned — they produce richer o
 | Command | TUI behavior |
 |---------|--------------|
 | `/help` | Overlay with categorized commands, arrow-key navigable |
-| `/sessions` | Modal session picker — preview, title, token totals, resume inline |
+| `/sessions` (alias `/switch`) | Live session switcher — list open TUI sessions, switch between them, close them, or start another one |
 | `/model` | Modal model picker grouped by provider, with cost hints |
 | `/skin` | Live preview — theme change applies as you browse |
 | `/details` | Toggle verbose tool-call details (global or per-section) |
@@ -110,6 +110,31 @@ All slash commands work unchanged. A few are TUI-owned — they produce richer o
 
 Every other slash command (including installed skills, quick commands, and personality toggles) works identically to the classic CLI. See [Slash Commands Reference](../reference/slash-commands.md).
 
+## Live session switcher
+
+Use the live session switcher when you want one terminal to act as a dispatcher for several TUI sessions. It lists only sessions that are currently live in this TUI process; closed sessions remain saved transcripts and can still be reopened with `/resume` or `hermes --tui --resume <id-or-title>`.
+
+Open it with any of these:
+
+- `Ctrl+X` from the TUI.
+- `/sessions` or `/switch`.
+- `/sessions new` to create a fresh live session immediately.
+- Click the `N live sessions` count in the status line.
+
+<img alt="Hermes TUI Session Orchestrator with one live session and a +new row" src="/img/docs/tui-session-orchestrator/session-orchestrator.png" />
+
+<video controls muted loop playsInline src="/img/docs/tui-session-orchestrator/session-orchestrator-demo.mp4" title="Hermes TUI Session Orchestrator demo" />
+
+Inside the switcher:
+
+- `↑` / `↓` move the selection; mouse clicks select rows too.
+- `Enter` switches to the selected live session.
+- `Ctrl+D` closes the selected live session.
+- `Ctrl+N` starts a blank live session.
+- `Ctrl+R` refreshes the live-session list.
+- `Esc` closes the switcher.
+- Select `+new`, type a prompt, and press `Enter` to dispatch a new live session. Press `Tab` first if you want to choose a model just for that new session.
+
 ## LaTeX math rendering
 
 The TUI's markdown pipeline renders LaTeX math inline: `$E = mc^2$` and `$$\frac{a}{b}$$` render as Unicode-formatted math instead of the raw TeX source. Works for inline and block math; unsupported syntax falls back to showing the literal TeX wrapped in a code span so it remains copyable.