ext-keybindings + ext-stage-dock: config-driven dock-toggle-visible (Super+d)

- **ext-stage-dock**: exports a `Service` interface with `toggle_visible()`.
  The extension inherits from it and registers via `provide_service` in
  `activate()`. The method slides the dock in/out (using the existing RCSS
  transition) regardless of slot count; showing an empty dock is valid.
- **ext-keybindings**: new `Action::dock_toggle_visible` action, mapped from
  `"dock-toggle-visible"` in `unbox.toml [[keybind]]`, dispatched to the
  stage-dock Service. Default binding: `Super+d`.
- **Manifest**: ext-keybindings now `depends_on {"xdg-shell", "stage-dock"}`.
- **Build**: subdir order swapped so ext-stage-dock builds before
  ext-keybindings; `ext_stage_dock_dep` is a link-time dep of the
  ext-keybindings library and transitively exposed via `ext_keybindings_dep`.
- **Tests**: glue tests install ext-stage-dock alongside ext-xdg-shell;
  policy test expects 6 default bindings. All 10/10 green on build +
  build-asan.

Configure in unbox.toml:
  [[keybind]]
  keys    = "Super+d"
  action  = "dock-toggle-visible"

1 files changed, 5 insertions, 3 deletions

diff --git a/packages/ext-keybindings/tests/test_policy.cpp b/packages/ext-keybindings/tests/test_policy.cpp
index 8b6b91b..d7fd32e 100644
--- a/packages/ext-keybindings/tests/test_policy.cpp
+++ b/packages/ext-keybindings/tests/test_policy.cpp
@@ -165,7 +165,7 @@ TEST_CASE("empty / keybind-less document yields zero bindings, not an error") {
 
 TEST_CASE("compiled defaults match the documented out-of-the-box set") {
     auto d = pol::default_bindings();
-    REQUIRE(d.size() == 5);
+    REQUIRE(d.size() == 6);
     CHECK(d[0].combo.is_tap);
     CHECK(d[0].combo.modifiers == pol::mod_logo);
     CHECK(d[0].action == Action::spawn);
@@ -178,6 +178,8 @@ TEST_CASE("compiled defaults match the documented out-of-the-box set") {
     CHECK(d[3].action == Action::focus_next);
     CHECK(d[4].combo == parse_combo("Ctrl+Alt+BackSpace").value());
     CHECK(d[4].action == Action::quit);
+    CHECK(d[5].combo == parse_combo("Super+d").value());
+    CHECK(d[5].action == Action::dock_toggle_visible);
 }
 
 // ============================================================================
@@ -236,11 +238,11 @@ TEST_CASE("reload: a valid-but-empty doc keeps the old table (never drops workin
     // mid-edit with the [[keybind]] block deleted, or every entry malformed)
     // must NOT swap — the user's live keys survive.
     std::vector<Binding> live = pol::default_bindings();
-    REQUIRE(live.size() == 5);
+    REQUIRE(live.size() == 6);
 
     auto empty = cfg::reload_bindings(live, "title = \"unrelated\"\n");
     CHECK_FALSE(empty.swapped);
-    REQUIRE(empty.bindings.size() == 5);
+    REQUIRE(empty.bindings.size() == 6);
     CHECK(empty.bindings == live); // kept
 
     // Same for a doc where every entry is individually skipped (all malformed).