macos: do not send UTF-8 PUA codepoints to key events

Fixes #7337

AppKit encodes functional keys as PUA codepoints. We don't want to send
that down as valid text encoding for a key event because KKP uses that
in particular to change the encoding with associated text.

I think there may be a more specific solution to this by only doing this
within the KKP encoding part of KeyEncoder but that was filled with edge
cases and I didn't want to risk breaking anything else.

macos/Sources/Ghostty/NSEvent+Extension.swift

@@ -56,13 +56,20 @@ extension NSEvent {
         // If we have no characters associated with this event we do nothing.
         guard let characters else { return nil }
 
-        // If we have a single control character, then we return the characters
-        // without control pressed. We do this because we handle control character
-        // encoding directly within Ghostty's KeyEncoder.
         if characters.count == 1,
-            let scalar = characters.unicodeScalars.first,
-            scalar.value < 0x20 {
-            return self.characters(byApplyingModifiers: modifierFlags.subtracting(.control))
+           let scalar = characters.unicodeScalars.first {
+            // If we have a single control character, then we return the characters
+            // without control pressed. We do this because we handle control character
+            // encoding directly within Ghostty's KeyEncoder.
+            if scalar.value < 0x20 {
+                return self.characters(byApplyingModifiers: modifierFlags.subtracting(.control))
+            }
+
+            // If we have a single value in the PUA, then it's a function key and
+            // we don't want to send PUA ranges down to Ghostty.
+            if scalar.value >= 0xF700 && scalar.value <= 0xF8FF {
+                return nil
+            }
         }
 
         return characters

src/input/KeyEncoder.zig

@@ -146,7 +146,9 @@ fn kitty(
                 // the real world issue is usually control characters.
                 const view = try std.unicode.Utf8View.init(self.event.utf8);
                 var it = view.iterator();
-                while (it.nextCodepoint()) |cp| if (isControl(cp)) break :plain_text;
+                while (it.nextCodepoint()) |cp| {
+                    if (isControl(cp)) break :plain_text;
+                }
 
                 return try copyToBuf(buf, self.event.utf8);
             }
@@ -212,7 +214,9 @@ fn kitty(
             }
         }
 
-        if (self.kitty_flags.report_associated and seq.event != .release) associated: {
+        if (self.kitty_flags.report_associated and
+            seq.event != .release)
+        associated: {
             // Determine if the Alt modifier should be treated as an actual
             // modifier (in which case it prevents associated text) or as
             // the macOS Option key, which does not prevent associated text.

src/terminal/kitty/key.zig

@@ -83,6 +83,15 @@ pub const Flags = packed struct(u5) {
     report_all: bool = false,
     report_associated: bool = false,
 
+    /// Sets all modes on.
+    pub const @"true": Flags = .{
+        .disambiguate = true,
+        .report_events = true,
+        .report_alternates = true,
+        .report_all = true,
+        .report_associated = true,
+    };
+
     pub fn int(self: Flags) u5 {
         return @bitCast(self);
     }