Reach Settings/Profile from the pause menu, with a way back

The pause menu (Escape during a question/CCS/flashcards run) only had
Resume/UI Sounds/Exit Run/Log Out. Settings already has an equivalent
"Interface sounds" toggle, so drop the duplicate from the pause menu.
More importantly, "player" and "ccs_player" hide the entire app shell
(header + sidebar), so there was no way to reach Settings or Profile
at all mid-session - add Profile/Settings buttons to the pause menu to
close that gap.

Navigating there follows the existing return_screen payload
convention (already used by simulation_history/results/review) rather
than inventing new navigation infrastructure: _navigate_from_pause()
remembers current_screen_name and passes it through show_screen's
payload. Both screens show a "Back to session" button when that's
set, and hide it otherwise (including on ordinary non-paused visits).

show_screen() unconditionally resumes the question timer via
_close_app_menu() as a side effect of any navigation, so
_navigate_from_pause() re-pauses it immediately when leaving "player" -
the timer then resumes for real, for free, when the user actually
returns via show_screen(return_screen).

progress_profile.gd rebuilds its whole child tree on every theme
toggle (_rebuild -> _build), which would otherwise wipe the button's
visibility - added _refresh_back_to_session_visibility(), called both
after _build() and from on_show(), so it survives a theme change while
paused.

Flipped tests/web_responsive_test.gd's assertion, which previously
required the pause menu NOT to have a Profile button.

Verified end-to-end headlessly: opening the pause menu from a live
"player" session, navigating to Settings and Profile, confirming
current_question_pause_started_at is correctly paused while away and
resumed on return, confirming the back-to-session button appears only
when reached via pause (not on ordinary nav), and confirming it
survives a dark/light theme toggle on the Profile screen.

scripts/ui/progress_profile.gd

@@ -19,6 +19,8 @@ var outcome_consent: CheckBox
 var outcome_status: Label
 var outcome_delete: Button
 var connected_accounts_list: VBoxContainer
+var return_screen := ""
+var back_to_session_button: Button
 
 
 func _ready() -> void:
@@ -38,7 +40,10 @@ func _ready() -> void:
 	_build()
 
 
-func on_show(_payload: Variant = null) -> void:
+func on_show(payload: Variant = null) -> void:
+	var wrapper: Dictionary = payload if typeof(payload) == TYPE_DICTIONARY else {}
+	return_screen = str(wrapper.get("return_screen", ""))
+	_refresh_back_to_session_visibility()
 	_render()
 	AccountProfileService.refresh()
 	DashboardService.refresh()
@@ -63,6 +68,11 @@ func _build() -> void:
 	status_label = _label("", 13, Brand.muted_color(_dark()))
 	status_label.visible = false
 	page.add_child(status_label)
+	back_to_session_button = _button("Back to session", "", true)
+	back_to_session_button.size_flags_horizontal = Control.SIZE_SHRINK_BEGIN
+	UISoundService.set_button_sound(back_to_session_button, "back")
+	back_to_session_button.pressed.connect(_return_to_session)
+	page.add_child(back_to_session_button)
 	columns = GridContainer.new()
 	columns.columns = 2
 	columns.size_flags_horizontal = Control.SIZE_EXPAND_FILL
@@ -87,6 +97,7 @@ func _build() -> void:
 	right.add_child(_outcome_card())
 	right.add_child(_connected_accounts_card())
 	right.add_child(_account_actions_card())
+	_refresh_back_to_session_visibility()
 	_update_responsive()
 	_render()
 
@@ -510,6 +521,17 @@ func _button(text: String, icon_name: String = "", primary: bool = false) -> But
 	return button
 
 
+func _refresh_back_to_session_visibility() -> void:
+	if back_to_session_button != null:
+		back_to_session_button.visible = not return_screen.is_empty()
+
+
+func _return_to_session() -> void:
+	if return_screen.is_empty():
+		return
+	main.show_screen(return_screen)
+
+
 func _action_button(text: String, icon_name: String, color: Color = Color.TRANSPARENT) -> Button:
 	var button := _button(text, icon_name, false)
 	button.alignment = HORIZONTAL_ALIGNMENT_LEFT