Add per-account toggle to disable automatic transaction categorization (#2636)

* Add per-account toggle to disable automatic transaction categorization

Adds an `enable_category_matcher` boolean (default: true) to accounts so
users can opt out of Plaid's automatic category suggestions on a per-account
basis. When disabled, newly synced transactions arrive uncategorized so
rules or manual assignment take precedence.

- New migration adds `enable_category_matcher` column (default true, null: false)
- `PlaidEntry::Processor#matched_category` gates the CategoryMatcher call on the account flag
- Toggle rendered in the account edit modal for linked accounts (saves via main form submit)
- `AccountableResource#account_params` permits the new field
- `AccountsController#toggle_category_matcher` action added for potential API use
- i18n strings added for label and hint text
- Unit test covers the disabled-matcher path

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Only show category matcher toggle for Plaid-linked accounts

Only PlaidEntry::Processor honors enable_category_matcher, but the toggle
rendered for every linked account, silently doing nothing for other
providers. Adds Account::Linkable#supports_category_matcher? (covering both
the legacy plaid_account_id link and AccountProvider rows) and gates the
form toggle on it. The SimpleFIN TODO now also points at this helper so the
toggle appears once SimpleFIN matching lands.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Add controller tests for category matcher toggle persistence and rendering

Covers the two paths flagged in review as untested: the flag persisting
through the shared AccountableResource#update action via account_params
(both disable and re-enable), and the edit form rendering the toggle only
for accounts where supports_category_matcher? is true.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Signed-off-by: Mike Lloyd <49411532+mike-lloyd03@users.noreply.github.com>
Signed-off-by: Juan José Mata <juanjo.mata@gmail.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Juan José Mata <juanjo.mata@gmail.com>

test/models/plaid_entry/processor_test.rb

@@ -89,4 +89,35 @@ class PlaidEntry::ProcessorTest < ActiveSupport::TestCase
     assert_equal "Amazon", entry.name
     assert_equal categories(:food_and_drink).id, entry.transaction.category_id
   end
+
+  test "skips category matcher when account.enable_category_matcher is false" do
+    @plaid_account.current_account.update!(enable_category_matcher: false)
+
+    plaid_transaction = {
+      "transaction_id" => "456",
+      "merchant_name" => "Amazon",
+      "amount" => 100,
+      "date" => Date.current,
+      "iso_currency_code" => "USD",
+      "personal_finance_category" => {
+        "detailed" => "Food"
+      },
+      "merchant_entity_id" => "456"
+    }
+
+    @category_matcher.expects(:match).never
+
+    processor = PlaidEntry::Processor.new(
+      plaid_transaction,
+      plaid_account: @plaid_account,
+      category_matcher: @category_matcher
+    )
+
+    assert_difference [ "Entry.count", "Transaction.count" ], 1 do
+      processor.process
+    end
+
+    entry = Entry.order(created_at: :desc).first
+    assert_nil entry.transaction.category_id
+  end
 end