fix: restore Ctrl+Alt+Key hotkeys and dedup normalizeHotkey

- Call enableVTInput after tea.NewProgram to restore VT input mode
  on Windows (bubbletea v1 conInputReader disables it, breaking
  Ctrl+Alt+Key combos)
- Move normalizeHotkey to internal/config.NormalizeHotkey, eliminate
  duplicate implementations in tui and console packages
- Remove unused Sess() getter from App

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/config/config.go

@@ -4,6 +4,7 @@ package config
 import (
 	"fmt"
 	"os"
+	"strings"
 	"time"
 )
 
@@ -28,6 +29,15 @@ type Config struct {
 	HotkeyMod   string
 }
 
+// NormalizeHotkey validates and normalizes a hotkey modifier string.
+func NormalizeHotkey(mod string) string {
+	mod = strings.ToLower(strings.TrimSpace(mod))
+	if mod != "ctrl+alt" && mod != "ctrl+shift" {
+		mod = "ctrl+alt"
+	}
+	return mod
+}
+
 // OpenLogFile opens the configured log file for writing, or returns nil if logging is disabled.
 func OpenLogFile(cfg *Config) (*os.File, error) {
 	if cfg.EnableLog {