fix(calendar): persist settings on PUT/POST

Accept calendar.settings (e.g. week_patterns) in validate_update
and convert_field; apply on create like tags. Unblocks Front#42
pattern save which previously got 200 with empty settings.

test/api/users/user_calendar_by_id_tests.erl

@@ -23,6 +23,7 @@ test() ->
   test_get_calendar_unauthorized(CalId),
   test_get_calendar_not_found(Token),
   test_update_calendar(Token, CalId),
+  test_update_calendar_settings(Token, CalId),
   test_update_calendar_forbidden(OtherToken, CalId),
   test_delete_calendar(Token, CalId),
   test_delete_calendar_forbidden(OtherToken, CalId),
@@ -60,6 +61,26 @@ test_update_calendar(Token, CalId) ->
   ?assertEqual(<<"New desc">>, maps:get(<<"description">>, Updated)),
   ct:pal("    OK").
 
+test_update_calendar_settings(Token, CalId) ->
+  ct:pal("  TEST: Persist calendar.settings.week_patterns"),
+  Path = <<"/v1/calendars/", CalId/binary>>,
+  Settings = #{
+    <<"week_patterns">> => [
+      #{
+        <<"id">> => <<"pat1">>,
+        <<"name">> => <<"Mon-Fri">>,
+        <<"slots">> => [
+          #{<<"weekday">> => 1, <<"time">> => <<"10:00">>, <<"duration">> => 60, <<"title">> => <<"Open">>}
+        ]
+      }
+    ]
+  },
+  Updated = api_test_runner:client_put(Path, Token, #{settings => Settings}),
+  ?assertEqual(Settings, maps:get(<<"settings">>, Updated)),
+  Got = api_test_runner:client_get(Path, Token),
+  ?assertEqual(Settings, maps:get(<<"settings">>, Got)),
+  ct:pal("    OK").
+
 test_update_calendar_forbidden(OtherToken, CalId) ->
   ct:pal("  TEST: Update calendar by non-owner (403)"),
   Path = <<"/v1/calendars/", CalId/binary>>,

test/unit/logic_calendar_tests.erl

@@ -35,6 +35,8 @@ logic_calendar_test_() ->
       {"Get calendar test", fun test_get_calendar/0},
       {"List calendars test", fun test_list_calendars/0},
       {"Update calendar test", fun test_update_calendar/0},
+      {"Persist calendar settings (week_patterns)", fun test_update_settings/0},
+      {"Reject non-map settings", fun test_update_settings_invalid/0},
       {"Delete calendar test", fun test_delete_calendar/0},
       {"Access control test", fun test_access_control/0},
       {"Ensure default calendar test", fun test_ensure_default_calendar/0}
@@ -117,6 +119,39 @@ test_update_calendar() ->
   ?assertMatch({error, access_denied},
     logic_calendar:update_calendar(OtherUserId, Calendar#calendar.id, Updates)).
 
+test_update_settings() ->
+  UserId = create_test_user(),
+  {ok, Calendar} = logic_calendar:create_calendar(UserId, <<"Studio">>, <<"">>, manual),
+  Patterns = [
+    #{
+      <<"id">> => <<"p1">>,
+      <<"name">> => <<"Weekdays">>,
+      <<"updated_at">> => <<"2026-07-29T12:00:00Z">>,
+      <<"slots">> => [
+        #{<<"weekday">> => 1, <<"time">> => <<"10:00">>, <<"duration">> => 60, <<"title">> => <<"Open">>}
+      ]
+    }
+  ],
+  Settings = #{<<"week_patterns">> => Patterns},
+  {ok, Updated} = logic_calendar:update_calendar(
+    UserId, Calendar#calendar.id, [{settings, Settings}]),
+  ?assertEqual(Settings, Updated#calendar.settings),
+  {ok, Reloaded} = logic_calendar:get_calendar(UserId, Calendar#calendar.id),
+  ?assertEqual(Settings, Reloaded#calendar.settings),
+  %% binary key path (as from raw JSON list before convert_field)
+  Settings2 = Settings#{<<"foo">> => <<"bar">>},
+  {ok, Updated2} = logic_calendar:update_calendar(
+    UserId, Calendar#calendar.id, [{<<"settings">>, Settings2}]),
+  ?assertEqual(Settings2, Updated2#calendar.settings).
+
+test_update_settings_invalid() ->
+  UserId = create_test_user(),
+  {ok, Calendar} = logic_calendar:create_calendar(UserId, <<"Studio">>, <<"">>, manual),
+  %% non-map settings silently dropped by validate_updates — calendar unchanged
+  {ok, Same} = logic_calendar:update_calendar(
+    UserId, Calendar#calendar.id, [{settings, [<<"not-a-map">>]}]),
+  ?assertEqual(#{}, Same#calendar.settings).
+
 test_delete_calendar() ->
   UserId = create_test_user(),
   {ok, Calendar} = logic_calendar:create_calendar(UserId, <<"Test">>, <<"">>, manual),