Remove hexai-tmux-edit popup editor featurev0.42.0

The tmux popup editor and its per-agent detection (Cursor/Amp/Aider)
added maintenance surface without enough use to justify it; Codex and
Claude Code already support external-editor mode natively via Ctrl+G.
Drops internal/tmuxedit, cmd/hexai-tmux-edit, the [tmux_edit] config
schema, the Mage build target, and all related docs/README mentions.

Bump version to 0.42.0.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 0 insertions, 45 deletions

diff --git a/internal/tmuxedit/capture_test.go b/internal/tmuxedit/capture_test.go
deleted file mode 100644
index c5a6605..0000000
--- a/internal/tmuxedit/capture_test.go
+++ /dev/null
@@ -1,45 +0,0 @@
-package tmuxedit
-
-import (
-	"fmt"
-	"testing"
-)
-
-func TestCapturePane_Success(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(name string, args ...string) ([]byte, error) {
-		if name == "tmux" && len(args) >= 3 && args[0] == "capture-pane" {
-			return []byte("Claude Code v1.0\n> hello world\n"), nil
-		}
-		return nil, fmt.Errorf("unexpected: %s %v", name, args)
-	}}
-	got, err := deps.capture("%5")
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-	if got != "Claude Code v1.0\n> hello world" {
-		t.Errorf("got %q, want trimmed content", got)
-	}
-}
-
-func TestCapturePane_Error(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(string, ...string) ([]byte, error) {
-		return nil, fmt.Errorf("pane not found")
-	}}
-	_, err := deps.capture("%999")
-	if err == nil {
-		t.Fatal("expected error for failed capture")
-	}
-}
-
-func TestCapturePane_EmptyContent(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(string, ...string) ([]byte, error) {
-		return []byte("\n\n"), nil
-	}}
-	got, err := deps.capture("%1")
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-	if got != "" {
-		t.Errorf("got %q, want empty string", got)
-	}
-}