Polish localization: complete translations, pluralization fixes, and reusable locale audit tooling (#1356)

* Add production-ready Polish localization and reusable locale audit tooling

- add and update Polish locale files across models, views, mailers, and shared translations
- add runtime rails-i18n dependency and Polish locale support in language helper
- add regression coverage for Polish pluralization and locale-aware money formatting
- introduce reusable locale audit script for any locale plus backward-compatible PL wrapper
- add localization audit docs and generated PL readiness/pluralization reports
- resolve one/few/many/other pluralization consistency for Polish locales

* Fix Polish locale review feedback

* Fix locale compatibility regressions

* Polish locale typo pass and wrapper cleanup

* Final language improvements and test isolation for Polish locales

- Improved partial_success wording in SnapTrade with proper noun inflection
- Fixed typos: Pomin → Pomiń in Mercury and LunchFlow items
- Isolated I18n backend state in polish_pluralization_test to prevent test coupling

* Fix code review comments in locale audit scripts

- Use RbConfig.ruby instead of 'ruby' to ensure consistent interpreter
- Remove Symbol from permitted_classes and explicitly allow CLDR plural symbols (one, few, many, other) in YAML loading

* Simplify i18n flow and align locale interpolation keys

* Remove locale audit scripts and localization docs

app/controllers/snaptrade_items_controller.rb

@@ -221,8 +221,9 @@ class SnaptradeItemsController < ApplicationController
 
       if errors.any?
         # Partial success - some linked, some failed
-        redirect_to accounts_path, notice: t(".partial_success", linked: linked_count, failed: errors.size,
-                                              default: "Linked #{linked_count} account(s). #{errors.size} failed to link.")
+        redirect_to accounts_path,
+                    notice: t(".partial_success", count: linked_count, failed_count: errors.size,
+                              default: "Linked #{linked_count} account(s). #{errors.size} failed to link.")
       else
         redirect_to accounts_path, notice: t(".success", count: linked_count, default: "Successfully linked #{linked_count} account(s).")
       end