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, 73 deletions

diff --git a/internal/tmuxedit/pane_test.go b/internal/tmuxedit/pane_test.go
deleted file mode 100644
index d15ef55..0000000
--- a/internal/tmuxedit/pane_test.go
+++ /dev/null
@@ -1,73 +0,0 @@
-package tmuxedit
-
-import (
-	"fmt"
-	"testing"
-)
-
-func TestResolveTargetPane_FlagWins(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(string, ...string) ([]byte, error) {
-		return []byte("%99"), nil
-	}}
-	t.Setenv("HEXAI_TMUX_PANE", "%10")
-	got, err := deps.resolveTargetPane("%5")
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-	if got != "%5" {
-		t.Errorf("got %q, want %%5 (flag should win)", got)
-	}
-}
-
-func TestResolveTargetPane_EnvFallback(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(string, ...string) ([]byte, error) {
-		return []byte("%99"), nil
-	}}
-	t.Setenv("HEXAI_TMUX_PANE", "%10")
-	got, err := deps.resolveTargetPane("")
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-	if got != "%10" {
-		t.Errorf("got %q, want %%10 (env fallback)", got)
-	}
-}
-
-func TestResolveTargetPane_TmuxQuery(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(name string, args ...string) ([]byte, error) {
-		if name == "tmux" && len(args) > 0 && args[0] == "display-message" {
-			return []byte("%42\n"), nil
-		}
-		return nil, fmt.Errorf("unexpected command: %s", name)
-	}}
-	t.Setenv("HEXAI_TMUX_PANE", "")
-	got, err := deps.resolveTargetPane("")
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-	if got != "%42" {
-		t.Errorf("got %q, want %%42 (tmux query)", got)
-	}
-}
-
-func TestResolveTargetPane_TmuxError(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(string, ...string) ([]byte, error) {
-		return nil, fmt.Errorf("tmux not available")
-	}}
-	t.Setenv("HEXAI_TMUX_PANE", "")
-	_, err := deps.resolveTargetPane("")
-	if err == nil {
-		t.Fatal("expected error when tmux fails")
-	}
-}
-
-func TestResolveTargetPane_TmuxEmptyOutput(t *testing.T) {
-	deps := tmuxEditDeps{runCommand: func(string, ...string) ([]byte, error) {
-		return []byte("  \n"), nil
-	}}
-	t.Setenv("HEXAI_TMUX_PANE", "")
-	_, err := deps.resolveTargetPane("")
-	if err == nil {
-		t.Fatal("expected error for empty tmux output")
-	}
-}