Update storing of virtual path for deep nesting

[thewatts]

What are you trying to accomplish?

Fix translation scope resolution in deeply nested component blocks (3+ levels). Currently, translations called inside deeply nested slot blocks using renders_many/renders_one incorrectly resolve to an intermediate component's scope instead of the partial's scope where the block was defined.

Example of the bug:

<!-- In app/views/shared/_action_menu_panel.html.erb -->
<%= render ActionMenuComponent.new do |menu| %>
  <% menu.with_list do |list| %>
    <% list.with_item do %>
      <%= t(".menu_action") %>  <!-- Should resolve to shared.action_menu_panel.menu_action -->
    <% end %>
  <% end %>
<% end %>

The translation incorrectly resolves to action_list_component.menu_action instead of shared.action_menu_panel.menu_action.

Builds on #2389.
Fixes #2386.

What approach did you choose and why?

The previous fix in #2389 added with_original_virtual_path, which restored the virtual path one level up to the immediate parent component.

This worked for 2-level nesting:

<!-- Partial → Component → Block (2 levels) -->
<%= render MyComponent.new do %>
  <%= t(".title") %>  <!-- Works correctly -->
<% end %>

But failed for 3+ level nesting:

<!-- Partial → Component1 → Component2 → Block (3 levels) -->
<%= render ActionMenuComponent.new do |menu| %>
  <% menu.with_list do |list| %>
    <% list.with_item do %>
      <%= t(".menu_action") %>  <!-- Resolved to wrong scope -->
    <% end %>
  <% end %>
<% end %>

The issue: The method only went one level up to the immediate parent, not all the way back to the original partial.

Approach: Capture the virtual path at block definition time instead of trying to walk back up the component hierarchy at execution time.

Implementation details:

1. In slotable.rb (line 397): When a block is provided to a slot method (e.g., with_item), capture the current @virtual_path and store it on the slot as __vc_content_block_virtual_path
2. In slot.rb (lines 61, 71): When executing the block, call @parent.with_captured_virtual_path(@__vc_content_block_virtual_path) to temporarily restore the captured path
3. In base.rb (line 384): The with_captured_virtual_path method takes the captured path as an explicit parameter and temporarily sets the virtual path during block execution

Why this approach:

• Works at any nesting depth (3, 5, 10+ levels) because the path is captured at definition time
• Simpler than walking up a component hierarchy
• Clear semantics: "Execute this block with the virtual path from where it was defined"

Alternative approaches considered:

• Walking the parent chain at execution time: More complex, requires tracking parent references through the entire component tree
• Global path tracking on view context: Would pollute view context and cause issues with multiple component trees in the same view

Tradeoffs:

• Adds one instance variable (__vc_content_block_virtual_path) to each slot that has a block
• Slight memory overhead, but necessary to maintain correct translation scope

After this fix, deeply nested translations work correctly:

<!-- Now works at any nesting depth -->
<%= render ActionMenuComponent.new do |menu| %>
  <% menu.with_list do |list| %>
    <% list.with_item do %>
      <%= t(".menu_action") %>  <!-- Correctly resolves to shared.action_menu_panel.menu_action -->
    <% end %>
  <% end %>
<% end %>

Anything you want to highlight for special attention from reviewers?

Test coverage: Added comprehensive tests for both 3-level and 5-level nesting scenarios using simplified test components inspired by Primer's ActionMenu pattern. The tests verify that translations resolve to the partial's scope, not any intermediate component's scope.

Implementation note: This also consolidates the virtual path restoration logic by having all three execution contexts (main component content blocks, lambda slots, and component class slots) use the same with_captured_virtual_path method with an explicit parameter, making the behavior consistent everywhere.