macOS: Selection for Find feature (#10192)

Adds the `selection_for_search` action, with Cmd+E keybind by default.
This action inputs the currently selected text into the search field
without changing focus, matching standard macOS behavior.

Implements discussion #9776 and #10036

<details><summary>AI Disclosure</summary>
<p>

Tab completions with Codestral.
Reviewed by Gemini 3 Flash via chatting.
No Agentic coding tools were involved.

</p>
</details>

src/Surface.zig

@@ -5163,6 +5163,15 @@ pub fn performBindingAction(self: *Surface, action: input.Binding.Action) !bool
             );
         },
 
+        .search_selection => {
+            const selection = try self.selectionString(self.alloc) orelse return false;
+            return try self.rt_app.performAction(
+                .{ .surface = self },
+                .start_search,
+                .{ .needle = selection },
+            );
+        },
+
         .end_search => {
             // We only return that this was performed if we actually
             // stopped a search, but we also send the apprt end_search so

src/apprt/action.zig

@@ -313,7 +313,9 @@ pub const Action = union(Key) {
     /// A command has finished,
     command_finished: CommandFinished,
 
-    /// Start the search overlay with an optional initial needle.
+    /// Start the search overlay with an optional initial needle. If the
+    /// search is already active and the needle is non-empty, update the
+    /// current search needle and focus the search input.
     start_search: StartSearch,
 
     /// End the search overlay, clearing the search state and hiding it.

src/config/Config.zig

@@ -6585,6 +6585,12 @@ pub const Keybinds = struct {
                 .start_search,
                 .{ .performable = true },
             );
+            try self.set.putFlags(
+                alloc,
+                .{ .key = .{ .unicode = 'e' }, .mods = .{ .super = true } },
+                .search_selection,
+                .{ .performable = true },
+            );
             try self.set.putFlags(
                 alloc,
                 .{ .key = .{ .unicode = 'f' }, .mods = .{ .super = true, .shift = true } },

src/input/Binding.zig

@@ -368,6 +368,11 @@ pub const Action = union(enum) {
     /// If a previous search is active, it is replaced.
     search: []const u8,
 
+    /// Start a search for the current text selection. If there is no
+    /// selection, this does nothing. If a search is already active, this
+    /// changes the search terms.
+    search_selection,
+
     /// Navigate the search results. If there is no active search, this
     /// is not performed.
     navigate_search: NavigateSearch,
@@ -1284,6 +1289,7 @@ pub const Action = union(enum) {
             .cursor_key,
             .search,
             .navigate_search,
+            .search_selection,
             .start_search,
             .end_search,
             .reset,

src/input/command.zig

@@ -189,6 +189,12 @@ fn actionCommands(action: Action.Key) []const Command {
             .description = "Start a search if one isn't already active.",
         }},
 
+        .search_selection => comptime &.{.{
+            .action = .search_selection,
+            .title = "Search Selection",
+            .description = "Start a search for the current text selection.",
+        }},
+
         .end_search => comptime &.{.{
             .action = .end_search,
             .title = "End Search",