Improve investment activity labels UX and add convert-to-trade feature (#649)

* Add `investment_activity_label` to trades and enhance activity label handling

- Introduced `investment_activity_label` column to the `trades` table with a migration.
- Backfilled existing `trades` with activity labels based on quantity (`Buy`, `Sell`, or `Other`).
- Replaced `category_id` in trades with `investment_activity_label` for better alignment with transaction labels.
- Updated views and controllers to display and manage activity labels for trades.
- Added localized badge components for displaying and editing labels dynamically.
- Enhanced `PlaidAccount::Investments::TransactionsProcessor` to assign and process activity labels automatically.
- Added investment flows section to reports for tracking contributions and withdrawals.
- Refactored related tests and models for consistency and to ensure proper validation and filtering.

* Improve handling of `investment_activity_label`, trade type, and security selection in trades and transactions

- Refined label assignment logic in `trades_controller` to default to `Buy`/`Sell` based on transaction nature.
- Simplified security selection in `transactions_controller` by resolving via unique IDs or custom tickers.
- Streamlined UI for trade and transaction forms by updating dropdown options and label text.
- Enabled quick-edit badges to open `convert_to_trade` modal when applicable, enhancing flexibility.
- Adjusted tests and views to align with updated workflows and ensure consistent behavior.

* Improve handling of `investment_activity_label`, trade type, and security selection in trades and transactions

- Refined label assignment logic in `trades_controller` to default to `Buy`/`Sell` based on transaction nature.
- Simplified security selection in `transactions_controller` by resolving via unique IDs or custom tickers.
- Streamlined UI for trade and transaction forms by updating dropdown options and label text.
- Enabled quick-edit badges to open `convert_to_trade` modal when applicable, enhancing flexibility.
- Adjusted tests and views to align with updated workflows and ensure consistent behavior.

* Improve handling of `investment_activity_label`, trade type, and security selection in trades and transactions

- Refined label assignment logic in `trades_controller` to default to `Buy`/`Sell` based on transaction nature.
- Simplified security selection in `transactions_controller` by resolving via unique IDs or custom tickers.
- Streamlined UI for trade and transaction forms by updating dropdown options and label text.
- Enabled quick-edit badges to open `convert_to_trade` modal when applicable, enhancing flexibility.
- Adjusted tests and views to align with updated workflows and ensure consistent behavior.

* Add safeguard for `dropdownTarget` existence in quick edit controller

- Prevent errors by ensuring `dropdownTarget` is present before toggling its visibility.

* Fix undefined method 'category' for Trade on mobile view

Trade model uses investment_activity_label, not category. The upstream
merge introduced a call to trade.category which doesn't exist. Use the
activity label badge on mobile instead.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* Fix activity label logic for zero/blank quantity and sell inference

- Return `nil` for blank or zero quantity in `investment_activity_label_for`.
- Correct `is_sell` logic to use the amount’s sign properly in `transactions_controller`.

* Fix i18n key paths in transactions controller for convert_to_trade

- Update flash message translations to use full i18n paths.
- Use `BigDecimal` for quantity and price calculations to improve precision.

---------

Co-authored-by: Josh Waldrep <joshua.waldrep5+github@gmail.com>
Co-authored-by: luckyPipewrench <luckypipewrench@proton.me>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

app/views/transactions/_transaction.html.erb

@@ -78,13 +78,6 @@
                       </span>
                     <% end %>
 
-                    <%# Investment activity label badge %>
-                    <% if transaction.investment_activity_label.present? %>
-                      <span class="inline-flex items-center px-1.5 py-0.5 rounded text-xs font-medium bg-alpha-black-50 text-secondary" title="<%= t("transactions.transaction.activity_type_tooltip") %>">
-                        <%= t("transactions.activity_labels.#{transaction.investment_activity_label.parameterize(separator: '_')}") %>
-                      </span>
-                    <% end %>
-
                     <%# Pending indicator %>
                     <% if transaction.pending? %>
                       <span class="inline-flex items-center gap-1 text-xs font-medium rounded-full px-1.5 py-0.5 border border-secondary text-secondary" title="<%= t("transactions.transaction.pending_tooltip") %>">
@@ -144,7 +137,12 @@
       </div>
 
       <div class="hidden md:flex items-center gap-1 col-span-2">
-        <%= render "transactions/transaction_category", transaction: transaction, variant: "desktop" %>
+        <% if entry.account.investment? && !transaction.transfer? %>
+          <%# For investment accounts, show activity label instead of category %>
+          <%= render "investment_activity/quick_edit_badge", entry: entry, entryable: transaction %>
+        <% else %>
+          <%= render "transactions/transaction_category", transaction: transaction, variant: "desktop" %>
+        <% end %>
       </div>
 
       <div class="shrink-0 col-span-4 lg:col-span-2 ml-auto text-right">