Standardize password reveal to the in-field eye icon everywhere

Register, reset, and Steam-linking forms used a separate "Show
password" CheckButton row; the main login form already had the eye
icon embedded in the field itself. Generalized _add_password_reveal
(previously hardwired to a single tracked button) to support multiple
fields via password_reveal_entries, and used it for every password
field instead. Removed the now-unused _add_show_password.

Verified all 6 password fields (login, register x2, reset x2, steam)
get a working reveal button and there's no leftover "Show password"
checkbox anywhere.

scripts/ui/login_screen.gd

@@ -25,7 +25,7 @@ var reset_view: VBoxContainer
 var steam_view: VBoxContainer
 var login_input: LineEdit
 var password_input: LineEdit
-var password_reveal_button: Button
+var password_reveal_entries: Array[Dictionary] = []
 var registration_username_input: LineEdit
 var registration_email_input: LineEdit
 var registration_password_input: LineEdit
@@ -295,7 +295,8 @@ func _build_register_view() -> VBoxContainer:
 	registration_email_input = _add_field(view, "Email", "[email protected]")
 	registration_password_input = _add_field(view, "Password", "At least 8 characters", true)
 	registration_confirm_input = _add_field(view, "Confirm password", "Re-enter your password", true)
-	_add_show_password(view, [registration_password_input, registration_confirm_input])
+	_add_password_reveal(registration_password_input)
+	_add_password_reveal(registration_confirm_input)
 	registration_legal_check = _add_legal_consent(view)
 	_add_primary_button(view, "Create Account", _on_register_pressed)
 	_add_back_button(view, "Already have an account?  Sign in", "login")
@@ -313,7 +314,8 @@ func _build_reset_view() -> VBoxContainer:
 	reset_code_input.max_length = 6
 	reset_password_input = _add_field(reset_confirm_group, "New password", "At least 8 characters", true)
 	reset_confirm_input = _add_field(reset_confirm_group, "Confirm new password", "Re-enter your new password", true)
-	_add_show_password(reset_confirm_group, [reset_password_input, reset_confirm_input])
+	_add_password_reveal(reset_password_input)
+	_add_password_reveal(reset_confirm_input)
 	_add_primary_button(reset_confirm_group, "Update Password", _confirm_reset)
 	_add_back_button(view, "Back to sign in", "login")
 	reset_confirm_group.visible = false
@@ -334,7 +336,7 @@ func _build_steam_view() -> VBoxContainer:
 	steam_username_input = _add_field(view, "Username or email", "Choose a username")
 	steam_email_input = _add_field(view, "Email", "[email protected]")
 	steam_password_input = _add_field(view, "Password", "At least 8 characters", true)
-	_add_show_password(view, [steam_password_input])
+	_add_password_reveal(steam_password_input)
 	steam_legal_check = _add_legal_consent(view)
 	_add_primary_button(view, "Continue", _complete_steam)
 	_add_back_button(view, "Cancel external sign in", "login")
@@ -407,19 +409,9 @@ func _add_field(parent: VBoxContainer, label_text: String, placeholder: String,
 	return input
 
 
-func _add_show_password(parent: VBoxContainer, targets: Array) -> void:
-	var toggle := CheckButton.new()
-	toggle.text = "Show password"
-	toggle.toggled.connect(func(should_reveal: bool):
-		for target in targets:
-			target.secret = not should_reveal
-	)
-	parent.add_child(toggle)
-
-
 func _add_password_reveal(input: LineEdit) -> void:
 	var reveal := Button.new()
-	password_reveal_button = reveal
+	password_reveal_entries.append({"input": input, "button": reveal})
 	reveal.text = ""
 	reveal.tooltip_text = "Show password"
 	reveal.flat = true
@@ -588,8 +580,8 @@ func _apply_theme() -> void:
 	theme_button.add_theme_stylebox_override("normal", theme_normal)
 	theme_button.add_theme_stylebox_override("hover", theme_normal)
 	theme_button.add_theme_color_override("font_color", Brand.AMBER)
-	if password_reveal_button != null:
+	for entry in password_reveal_entries:
-		_refresh_password_reveal(password_input, password_reveal_button)
+		_refresh_password_reveal(entry["input"], entry["button"])
 	subheading.add_theme_color_override("font_color", Brand.muted_color(dark))
 	message_label.add_theme_color_override("font_color", Brand.muted_color(dark))
 	if brand_tagline != null: