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, 63 deletions

diff --git a/internal/tmuxedit/pane.go b/internal/tmuxedit/pane.go
deleted file mode 100644
index 2713994..0000000
--- a/internal/tmuxedit/pane.go
+++ /dev/null
@@ -1,63 +0,0 @@
-package tmuxedit
-
-import (
-	"fmt"
-	"os"
-	"os/exec"
-	"strings"
-)
-
-type tmuxEditDeps struct {
-	runCommand       func(string, ...string) ([]byte, error)
-	capturePane      func(string) (string, error)
-	openEditorPopup  func(string, string, string) (string, error)
-	sendKeys         func(string, ...string) error
-	sendRepeatedKey  func(string, string, int) error
-	sleepAfterClear  func()
-	sleepAfterEscape func()
-	launchPopup      func(string, string, string, string) error
-}
-
-func (d tmuxEditDeps) command(name string, args ...string) ([]byte, error) {
-	if d.runCommand != nil {
-		return d.runCommand(name, args...)
-	}
-	return exec.Command(name, args...).Output()
-}
-
-// resolveTargetPane determines which tmux pane to target using a fallback
-// chain: explicit flag > HEXAI_TMUX_PANE env var > tmux query for active pane.
-// Returns the pane ID (e.g. "%5") or an error.
-func resolveTargetPane(flagPane string) (string, error) {
-	return tmuxEditDeps{}.resolveTargetPane(flagPane)
-}
-
-func (d tmuxEditDeps) resolveTargetPane(flagPane string) (string, error) {
-	// 1. Explicit --pane flag
-	if p := strings.TrimSpace(flagPane); p != "" {
-		return p, nil
-	}
-	// 2. Environment variable
-	if p := strings.TrimSpace(os.Getenv("HEXAI_TMUX_PANE")); p != "" {
-		return p, nil
-	}
-	// 3. Query tmux for the active pane in the current window
-	return d.queryActivePane()
-}
-
-// queryActivePane asks tmux for the active pane ID using display-message.
-func queryActivePane() (string, error) {
-	return tmuxEditDeps{}.queryActivePane()
-}
-
-func (d tmuxEditDeps) queryActivePane() (string, error) {
-	out, err := d.command("tmux", "display-message", "-p", "#{pane_id}")
-	if err != nil {
-		return "", fmt.Errorf("cannot determine tmux pane: %w", err)
-	}
-	pane := strings.TrimSpace(string(out))
-	if pane == "" {
-		return "", fmt.Errorf("tmux returned empty pane ID")
-	}
-	return pane, nil
-}