Add way back to profile selection and abandoning a mission

World map gets a "Changer de profil" button (saves first). During a
mission, a header button asks for confirmation then leaves without
stars or items; attempts already made stay recorded and are saved.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

tests/exercises/test_exercise_host_abandon.gd

@@ -0,0 +1,50 @@
+extends GutTest
+## Quitter une mission en cours : confirmation demandee, aucune etoile ni
+## aucun objet, jamais compte comme un echec. Le changement de scene n'est
+## pas observe ici (voir point 14 de docs/specs/decisions.md).
+
+var _profile_id: String = ""
+
+
+func before_each() -> void:
+    _profile_id = ProfileManager.create_profile("Test", "CE1")
+    ProfileManager.select_profile(_profile_id)
+    GameManager.pending_mission_id = "mission_01_pre_des_mots"
+
+
+func after_each() -> void:
+    ProfileManager.delete_profile(_profile_id)
+    GameManager.pending_mission_id = ""
+    GameManager.last_outcomes = []
+
+
+func _open_host() -> Control:
+    var host: Control = load("res://scenes/exercises/exercise_host.tscn").instantiate()
+    add_child_autofree(host)
+    await wait_process_frames(1)
+    return host
+
+
+func test_abandon_asks_for_confirmation_before_leaving() -> void:
+    var host: Control = await _open_host()
+
+    var dialog: ConfirmationDialog = host.get_node("%AbandonConfirmDialog")
+    assert_false(dialog.visible)
+    assert_eq((host.get_node("%AbandonButton") as Button).text, "Quitter la mission")
+
+    host.get_node("%AbandonButton").pressed.emit()
+    await wait_process_frames(1)
+
+    assert_true(dialog.visible, "la confirmation doit s'afficher avant de quitter")
+    assert_eq(GameManager.pending_mission_id, "mission_01_pre_des_mots", "pas encore parti")
+
+
+func test_confirmed_abandon_gives_no_stars_and_clears_the_mission() -> void:
+    var host: Control = await _open_host()
+
+    host.get_node("%AbandonConfirmDialog").confirmed.emit()
+
+    assert_eq(GameManager.pending_mission_id, "")
+    assert_eq(ProgressManager.stars(), 0)
+    assert_eq(ProgressManager.mission_best_stars("mission_01_pre_des_mots"), 0)
+    assert_eq(ProgressManager.owned_items(), [])

tests/world/test_world_map.gd

@@ -43,3 +43,12 @@ func test_ce2_profile_sees_ce2_missions_and_can_review_ce1() -> void:
     toggle.pressed.emit()
     await wait_process_frames(1)
     assert_eq(map.get_node("%MapArea").get_child_count(), 12)
+
+
+func test_map_offers_a_way_back_to_the_profile_selection() -> void:
+    var map := _open_map_for("CE1")
+    await wait_process_frames(1)
+
+    var button: Button = map.get_node("%ProfileButton")
+    assert_true(button.visible)
+    assert_eq(button.text, UIText.get_text("world_map.change_profile_button"))