Dismissible OPML Import Banner - Source Monitor

What Was Built

Dismissible OPML import banner on the sources index page. Users can now click an X button to dismiss the import history notification. Dismissed banners are hidden via a dismissed_at timestamp on the ImportHistory model, filtered out of the controller query, and removed from the DOM via Turbo Stream.

Tasks Completed

Task 1: Add dismissed_at migration (commit: a8eca76)
Task 2: Create import history dismissal endpoint (commit: 04ff496)
Task 3: Update banner partial with dismiss button (commit: 4b176e8)
Task 4: Filter dismissed imports from controller query (commit: 73d7e84)

Files Modified

db/migrate/20260305120000_add_dismissed_at_to_import_histories.rb (created)
test/dummy/db/schema.rb (modified - schema dump)
app/controllers/source_monitor/import_history_dismissals_controller.rb (created)
config/routes.rb (modified - added nested dismissal resource)
test/controllers/source_monitor/import_history_dismissals_controller_test.rb (created)
app/views/source_monitor/sources/_import_history_panel.html.erb (modified - added dismiss button)
app/models/source_monitor/import_history.rb (modified - added not_dismissed scope)
app/controllers/source_monitor/sources_controller.rb (modified - chained not_dismissed)
test/models/source_monitor/import_history_dismissed_test.rb (created)

Deviations

Used resource :dismissal (singular nested resource with POST) instead of PATCH /import_histories/:id/dismiss to follow the project's Everything-is-CRUD routing convention
404 test uses assert_response :not_found instead of assert_raises(ActiveRecord::RecordNotFound) because Rails integration tests convert exceptions to HTTP responses

Test Results

1228 runs, 3809 assertions, 0 failures, 0 errors, 0 skips
RuboCop: 0 offenses on all changed files