Expose key bindings over IPC so a launcher can list them

Asked whether srdwm's bindings show in the AGS launcher. They could not:
srd.bind lives entirely in the Lua engine, and nothing published a binding
anywhere a client could read it. There was no IPC command, no field in any
response, and bound_keys() was used only by main.rs to register grabs.

srd.bind now takes an optional third argument, a description, and the loaded
set is copied into the WindowManager after the initial load and after every
reload. Core neither owns nor interprets them - it has no Lua state and
never dispatches a key - it holds them so the IPC layer, which is handed a
WindowManager and nothing else, can serve them. New `srd keybindings` returns
combo and description pairs, sorted so a UI listing them does not reshuffle
on every refresh.

Every binding in the shipped config now carries a description, so the feature
is useful without the user writing any.

Verified live in a nested instance: 46 bindings published, 0 without a
description, and editing the config file updated the list without a restart
(which also exercised reload-on-write again).

Also verified, for the separate report that windows cannot be moved to
another workspace from the AGS workspace pills: the compositor side works.
`srd dispatch move workspace <id> 2` moved a window from workspace 1 to 2 and
correctly hid it, since workspace 1 was active. Nothing to fix here; the
missing piece is on the shell side.

515 tests pass, clippy clean.

1 files changed, 7 insertions, 1 deletions

diff --git a/crates/ctl/src/main.rs b/crates/ctl/src/main.rs
index 4689660..1153611 100644
--- a/crates/ctl/src/main.rs
+++ b/crates/ctl/src/main.rs
@@ -7,6 +7,7 @@
 //! Usage:
 //!   srd clients                        list windows, one JSON object
 //!   srd workspaces                     list workspaces, one JSON object
+//!   srd keybindings                    list key bindings and descriptions
 //!   srd settings                       current shadows/rounded_corners/
 //!                                       animations/night_light/reading_mode
 //!                                       state, one JSON object
@@ -144,6 +145,10 @@ fn build_request(args: &[String]) -> Result<String, String> {
         Some("clients") => Ok(r#"{"cmd":"clients"}"#.to_string()),
         Some("monitors") => Ok(r#"{"cmd":"monitors"}"#.to_string()),
         Some("workspaces") => Ok(r#"{"cmd":"workspaces"}"#.to_string()),
+        // Every binding the loaded config registered, with its description
+        // if it gave one - what a launcher or cheat-sheet needs to show
+        // the user their own keys.
+        Some("keybindings") => Ok(r#"{"cmd":"keybindings"}"#.to_string()),
         Some("settings") => Ok(r#"{"cmd":"settings"}"#.to_string()),
         Some("pinned") if args.get(1).map(String::as_str) == Some("inputs") => Ok(r#"{"cmd":"pinned_inputs"}"#.to_string()),
         Some("pinned") => Err("did you mean 'srd pinned inputs'?".to_string()),
@@ -221,7 +226,7 @@ fn build_request(args: &[String]) -> Result<String, String> {
             Ok(format!(r#"{{"cmd":"set","key":"{key}","value":{value}}}"#))
         }
         _ => Err(
-            "expected 'clients', 'monitors', 'workspaces', 'settings', 'keyboard layout', 'subscribe', 'dispatch <action> <id>', 'capture workspace <id> <path>', or 'set <key> <value>'"
+            "expected 'clients', 'monitors', 'workspaces', 'keybindings', 'settings', 'keyboard layout', 'subscribe', 'dispatch <action> <id>', 'capture workspace <id> <path>', or 'set <key> <value>'"
                 .to_string(),
         ),
     }
@@ -409,6 +414,7 @@ fn print_usage() {
     eprintln!("  srd clients");
     eprintln!("  srd monitors");
     eprintln!("  srd workspaces");
+    eprintln!("  srd keybindings");
     eprintln!("  srd settings");
     eprintln!("  srd pinned inputs");
     eprintln!("  srd keyboard layout");