feat(config): Add directional output selection via separate direction field

Add support for directional output selection in the move-to-output action
using a separate `direction` field instead of overloading OutputMatch.

API additions:
- Add Workspace::connector() to get the connector showing a workspace
- Add Connector::connector_in_direction() to find outputs directionally

Implementation:
- Move directional finding logic from toml-config to compositor
- Algorithm uses center-to-center distance with axis-aligned preference
- Add GetWorkspaceConnector and GetConnectorInDirection IPC messages

Configuration changes:
- Add optional `direction` field to move-to-output action
- Either `output` or `direction` must be specified (not both)
- Valid directions: "left", "right", "up", "down"

Example usage:
  logo+control+shift+right = { type = "move-to-output", direction = "right" }

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>

toml-spec/spec/spec.yaml

@@ -288,19 +288,29 @@ Action:
           description: |
             Moves a workspace to a different output.
             
-            - Example 1:
+            - Example 1: Move a specific workspace to a named output
             
               ```toml
               [shortcuts]
               alt-F1 = { type = "move-to-output", workspace = "1", output.name = "right" }
               ```
             
-            - Example 2:
+            - Example 2: Move the current workspace to a named output
             
               ```toml
               [shortcuts]
               alt-F1 = { type = "move-to-output", output.name = "right" }
               ```
+
+            - Example 3: Move the current workspace to the output on the right (directional)
+
+              ```toml
+              [shortcuts]
+              "logo+ctrl+shift+Right" = { type = "move-to-output", direction = "right" }
+              "logo+ctrl+shift+Left" = { type = "move-to-output", direction = "left" }
+              "logo+ctrl+shift+Up" = { type = "move-to-output", direction = "up" }
+              "logo+ctrl+shift+Down" = { type = "move-to-output", direction = "down" }
+              ```
           fields:
             workspace:
               description: |
@@ -315,8 +325,21 @@ Action:
                 
                 If multiple outputs match, the workspace is moved to the first matching
                 output.
-              required: true
+
+                Either `output` or `direction` must be specified, but not both.
+              required: false
               ref: OutputMatch
+            direction:
+              description: |
+                The direction to search for the next output.
+
+                Finds the closest output in the specified direction based on
+                center-to-center distance, with preference for outputs better aligned
+                with the movement axis.
+
+                Either `output` or `direction` must be specified, but not both.
+              required: false
+              ref: Direction
         configure-connector:
           description: |
             Applies a configuration to connectors.
@@ -4193,6 +4216,21 @@ BlendSpace:
       description: Linear color space. This is the physically correct blend space.
 
 
+Direction:
+  kind: string
+  description: |
+    A directional value used for output selection.
+  values:
+    - value: left
+      description: The left direction.
+    - value: right
+      description: The right direction.
+    - value: up
+      description: The up direction.
+    - value: down
+      description: The down direction.
+
+
 ClientCapabilities:
   description: |
     A mask of client capabilities.