feat: target selection with Tab, individual flee in solo

- Add targetCursor to Model; Tab cycles through monsters in combat
- Pass targetCursor to renderGame/renderHUD; show "> " marker on selected enemy
- Attack and Skill actions use targetCursor as TargetIdx
- Update action bar to show [Tab]Target hint
- Replace unanimous-flee block with per-player flee; solo mode transitions to PhaseExploring immediately on success

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/model.go

@@ -2,6 +2,7 @@ package ui
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"

ui/model_test.go

@@ -0,0 +1,113 @@
+package ui
+
+import (
+	"testing"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/tolelom/catacombs/game"
+	"github.com/tolelom/catacombs/store"
+	"os"
+)
+
+func testDB(t *testing.T) *store.DB {
+	db, err := store.Open("test_ui.db")
+	if err != nil {
+		t.Fatal(err)
+	}
+	return db
+}
+
+func TestTitleToLobby(t *testing.T) {
+	lobby := game.NewLobby()
+	db := testDB(t)
+	defer func() { db.Close(); os.Remove("test_ui.db") }()
+
+	m := NewModel(80, 24, "testfp", lobby, db)
+
+	if m.screen != screenTitle {
+		t.Fatalf("initial screen: got %d, want screenTitle(0)", m.screen)
+	}
+
+	// Press Enter
+	result, _ := m.Update(tea.KeyMsg{Type: tea.KeyEnter})
+	m2 := result.(Model)
+
+	if m2.screen != screenLobby {
+		t.Errorf("after Enter: screen=%d, want screenLobby(1)", m2.screen)
+	}
+	if m2.playerName == "" {
+		t.Error("playerName should be set")
+	}
+}
+
+func TestLobbyCreateRoom(t *testing.T) {
+	lobby := game.NewLobby()
+	db := testDB(t)
+	defer func() { db.Close(); os.Remove("test_ui.db") }()
+
+	m := NewModel(80, 24, "testfp", lobby, db)
+
+	// Go to lobby
+	result, _ := m.Update(tea.KeyMsg{Type: tea.KeyEnter})
+	m2 := result.(Model)
+
+	// Press 'c' to create room
+	result, _ = m2.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'c'}})
+	m3 := result.(Model)
+
+	if m3.screen != screenClassSelect {
+		t.Errorf("after 'c': screen=%d, want screenClassSelect(2)", m3.screen)
+	}
+	if m3.roomCode == "" {
+		t.Error("roomCode should be set")
+	}
+}
+
+func TestClassSelectToGame(t *testing.T) {
+	lobby := game.NewLobby()
+	db := testDB(t)
+	defer func() { db.Close(); os.Remove("test_ui.db") }()
+
+	m := NewModel(80, 24, "testfp", lobby, db)
+
+	// Title -> Lobby -> Class Select -> Game
+	result, _ := m.Update(tea.KeyMsg{Type: tea.KeyEnter})
+	m2 := result.(Model)
+	result, _ = m2.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'c'}})
+	m3 := result.(Model)
+
+	if m3.screen != screenClassSelect {
+		t.Fatalf("should be at class select, got %d", m3.screen)
+	}
+
+	// Press Enter to select Warrior (default cursor=0)
+	result, _ = m3.Update(tea.KeyMsg{Type: tea.KeyEnter})
+	m4 := result.(Model)
+
+	if m4.screen != screenGame {
+		t.Errorf("after class select Enter: screen=%d, want screenGame(3)", m4.screen)
+	}
+	if m4.session == nil {
+		t.Error("session should be set")
+	}
+}
+
+func TestKeyHelpers(t *testing.T) {
+	enter := tea.KeyMsg{Type: tea.KeyEnter}
+	if !isEnter(enter) {
+		t.Error("isEnter should match KeyEnter type")
+	}
+
+	enterStr := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'\r'}}
+	_ = enterStr // might not match, that's ok
+
+	up := tea.KeyMsg{Type: tea.KeyUp}
+	if !isUp(up) {
+		t.Error("isUp should match KeyUp type")
+	}
+
+	q := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'q'}}
+	if !isQuit(q) {
+		t.Error("isQuit should match 'q'")
+	}
+}