Honor bread.command.box.open via breadbox listen

EVENTS.md

@@ -8,16 +8,19 @@ specifically its "Namespaces" and "Integrating a bread\* app" sections —
 for the general convention this follows.
 
 App id: **`box`**. Transport: `bread-utils`'s `bread_client` module
-(feature `bread-client`) — `breadbox` links it directly. breadbox is a
-short-lived process (it exits when the launcher closes), so each `emit`
-is its own short-lived connection. There is no long-running daemon and
-therefore no command subscription.
+(feature `bread-client`) — `breadbox` links it directly. One-shot
+launcher invocations each `emit` on their own fire-and-forget
+connection. Command verbs are only received while `breadbox listen` is
+running — that process holds the `bread.command.box.**` subscription
+open.
 
 ## Events published (`bread.box.*`)
 
 | Event | Data | When |
 |-------|------|------|
 | `bread.box.launched` | `{ "id": "<desktop id or exec>", "name": "<display name>" }` | The user launched an app (Enter / keypad Enter on the selected row, or activating a row) **and** the spawn succeeded. Not emitted if `Command::spawn` fails (missing terminal, `exec` that cannot start). `id` is the desktop-file id (the `.desktop` filename, e.g. `firefox.desktop`), falling back to the stripped `Exec=` line when that id is empty. `name` is the desktop-entry display name. |
+| `bread.box.open.done` | `{}` | `bread.command.box.open` was received and `breadbox` was spawned. This is the command confirmation, not proof the overlay mapped — the spawned process is the same toggle as a keybind. |
+| `bread.box.open.failed` | `{ "error": "<message>" }` | `bread.command.box.open` was received but this binary could not be started. |
 
 Launch history is local to breadbox (`~/.cache/breadbox/history.json`);
 the event bus is a notification that a launch happened, not a channel
@@ -25,17 +28,38 @@ for the exec line's arguments or the resulting process.
 
 ## Commands honored (`bread.command.box.*`)
 
-None. breadbox is not a daemon — it is not running (and not subscribed)
-except while the launcher overlay is open. There is no existing
-"launch this desktop id from the bus" product surface, and inventing
-`bread.command.box.launch` (or similar) without that surface would be a
-stub. If/when breadbox grows a long-running piece that can honor a
-verb, the corresponding `bread.command.box.*` command should be added
-at the same time, not stubbed out ahead of it.
+These are only received while `breadbox listen` is running. Publishing a
+command with no subscriber is a silent no-op — that is the documented
+bread convention, not a breadbox bug.
+
+| Verb | Data | Effect |
+|------|------|--------|
+| `open` | none | Same as running `breadbox` (toggle the launcher overlay via the existing singleton). Emits `bread.box.open.done` / `.failed`. |
+
+```lua
+bread.spawn(function()
+    bread.emit("bread.command.box.open")
+    bread.wait("bread.box.open.done", { timeout = 5000 })
+end)
+```
+
+### Not implemented: extra verbs
+
+There is no `launch` / `close` / `query` command verb. Picking a desktop
+id from the bus would be a new product surface. If/when that exists, add
+the corresponding `bread.command.box.*` verb at the same time, not
+stubbed as a no-op ahead of it.
 
 ## Fail-safe behavior
 
 - If breadd isn't installed or isn't running, `emit` is a silent no-op
-  (`BreadClient::emit` never blocks or errors the caller) — launching,
+  (`BreadClient::emit` never blocks or errors the caller) and the
+  command subscription simply never receives anything — launching,
   history, theming, and the singleton toggle are entirely unaffected.
+- If breadd restarts, the command subscription reconnects automatically
+  (`BreadClient::subscribe`'s background thread has its own backoff
+  loop); no restart of `breadbox listen` is needed.
+- If `breadbox listen` is not running, commands are a graceful no-op at
+  the bus (no subscriber). The CLI still works, and one-shot invocations
+  still emit `bread.box.launched` on their own short-lived connection.
 - Closing the launcher without launching anything emits nothing.