Validate and normalize auto-postpone period to days (#2672)

* Validate and normalize auto-postpone period to days

- Add Entropy::AUTO_POSTPONE_PERIODS and validate auto_postpone_period against the allowed set
- Introduce auto_postpone_period_in_days for forms and entropy update endpoints
- Fall back to index 0 in knob partial when current value isn't in options
- Remove entropy_auto_close_options helper in favor of model constant
- Update tests to use allowed period values

* Use auto_postpone_period_in_days for JSON entropy updates

The JSON API was accepting auto_postpone_period (seconds) which
bypassed the days normalization and validation. Switch to
auto_postpone_period_in_days consistently and add explicit
wrap_parameters so flat JSON params are wrapped correctly for
the virtual attribute.

* Default to account or 30-day fallback when knob value is invalid

* Address PR review feedback for entropy validation

- Fall back to first knob option (index 0) when persisted value isn't in
  the allowed set, preventing nil index errors for legacy values
- Use integer division (1.day.to_i) for consistent day calculations

* Default to account entropy period instead of first option for knob fallback

* Test that default auto-postpone period is in the allowed periods

* Return 422 instead of 500 for invalid entropy auto-postpone values

Rescue ActiveRecord::RecordInvalid in entropy controllers so invalid
auto_postpone_period_in_days values return 422 Unprocessable Entity
instead of raising a 500.

* Fix NoMethodError when board entropy falls back to account default

Use container.account.entropy.auto_postpone_period_in_days instead of
container.account.auto_postpone_period_in_days since Account doesn't
delegate that method.

* Test board entropy fallback to account default for invalid periods

app/views/entropy/_auto_close.html.erb

@@ -6,8 +6,9 @@
     <%= form_with model: model, url: url, data: { controller: "form" } do |form| %>
       <%= render "entropy/knob",
             form: form,
-            name: :auto_postpone_period,
-            knob_options: entropy_auto_close_options,
+            name: :auto_postpone_period_in_days,
+            current_value: model.auto_postpone_period_in_days,
+            knob_options: Entropy::AUTO_POSTPONE_PERIODS_IN_DAYS,
             label: "Days until auto-close",
             disabled: disabled  %>
     <% end %>

app/views/entropy/_knob.html.erb

@@ -1,6 +1,5 @@
 <%
-  period = form.object.send(name)
-  current_index = knob_options.index(period.to_i / 1.day)
+  current_index = knob_options.index(current_value) || knob_options.index(Entropy::DEFAULT_AUTO_POSTPONE_PERIOD_IN_DAYS)
 %>
 
 <fieldset class="knob" data-controller="knob" data-knob-target="field" style="--knob-options: <%= knob_options.length %>; --knob-index: <%= current_index %>">
@@ -8,7 +7,7 @@
     <% knob_options.each_with_index do |value, index| %>
       <label class="knob__option" style="--i: <%= index %>">
         <%= form.radio_button name,
-              value.days,
+              value,
               data: {
                 action: "change->knob#optionChanged change->form#submit",
                 index: index,