feat(ai): пилотные метрики ИИ-подсказок — POST /v1/ai/hint-metrics + админ-сводка

Канон PRODUCT-AI (Spec#22): пилотные метрики L1-подсказок для расчёта
голосового гейта L2 (>=20% активных пользователей с >=2 подтверждённых
ghost-бронирований в месяц). Локальные счётчики в Mnesia, без LLM.

- таблица ai_hint_metric (миграция 20260820180000): счётчики
  {user, день UTC, pattern, kind}; ленивый prune при >500 строк на
  пользователя, retention 92 дня
- POST /v1/ai/hint-metrics (Bearer): батч <=20 событий shown/confirm/dismiss,
  202 {accepted:N}; ETS rate limit 30 req/min на пользователя
- GET /v1/admin/ai-metrics/stats (админ-порт): by_kind, active_users_30d,
  users_with_confirms_ge2_30d, gate_ratio_30d, top_patterns_by_confirm
- eunit logic_ai_metrics_tests (5/5); синхронизация списка миграций
  в migration_engine_tests

Refs EventHub/EventHubBack#78

test/unit/eh_test_support.erl

@@ -100,7 +100,8 @@ ensure_indexes(Tables) when is_list(Tables) ->
     {auth_session, [family_id, subject_id]},
     {report, [resolved_by]},
     {ticket, [assigned_to]},
-    {month_snapshot, [calendar_id, year_month]}
+    {month_snapshot, [calendar_id, year_month]},
+    {ai_hint_metric, [user_id, day]}
   ]),
   ok.
 
@@ -207,7 +208,9 @@ table_opts(node_metric) ->
 table_opts(schema_migration) ->
   [{ram_copies, [node()]}, {attributes, record_info(fields, schema_migration)}];
 table_opts(month_snapshot) ->
-  [{ram_copies, [node()]}, {attributes, record_info(fields, month_snapshot)}].
+  [{ram_copies, [node()]}, {attributes, record_info(fields, month_snapshot)}];
+table_opts(ai_hint_metric) ->
+  [{ram_copies, [node()]}, {attributes, record_info(fields, ai_hint_metric)}].
 
 %%%===================================================================
 %%% Domain seeds

test/unit/logic_ai_metrics_tests.erl

@@ -0,0 +1,75 @@
+%%%-------------------------------------------------------------------
+%%% EUnit: пилотные метрики ИИ-подсказок (logic_ai_metrics).
+%%%-------------------------------------------------------------------
+-module(logic_ai_metrics_tests).
+-include_lib("eunit/include/eunit.hrl").
+-include("records.hrl").
+
+-define(TABLES, [ai_hint_metric]).
+
+setup() ->
+  catch ets:delete(eventhub_ai_metrics_rl),
+  eh_test_support:start_mnesia(),
+  eh_test_support:ensure_tables(?TABLES),
+  ok.
+
+cleanup(_) ->
+  eh_test_support:delete_tables(?TABLES),
+  eh_test_support:stop_mnesia(),
+  catch ets:delete(eventhub_ai_metrics_rl),
+  ok.
+
+logic_ai_metrics_test_() ->
+  {foreach, fun setup/0, fun cleanup/1, [
+    {"invalid body rejected", fun test_invalid_body/0},
+    {"unknown kind rejected", fun test_unknown_kind/0},
+    {"counters increment per key", fun test_increment/0},
+    {"batch over limit rejected", fun test_batch_limit/0},
+    {"summary counts kinds and gate ratio", fun test_summary/0}
+  ]}.
+
+event(Kind, Pattern) ->
+  #{<<"kind">> => Kind, <<"pattern">> => Pattern}.
+
+test_invalid_body() ->
+  ?assertEqual({error, invalid_body}, logic_ai_metrics:record_events(<<"u1">>, [])),
+  ?assertEqual({error, invalid_body}, logic_ai_metrics:record_events(<<"u1">>, not_a_list)),
+  ?assertEqual({error, invalid_body},
+    logic_ai_metrics:record_events(<<"u1">>, [#{<<"kind">> => <<"shown">>}])).
+
+test_unknown_kind() ->
+  ?assertEqual({error, invalid_body},
+    logic_ai_metrics:record_events(<<"u1">>, [event(<<"click">>, <<"p">>)])),
+  ?assertEqual({error, invalid_body},
+    logic_ai_metrics:record_events(<<"u1">>, [event(<<"shown">>, <<>>)])).
+
+test_increment() ->
+  {ok, 2} = logic_ai_metrics:record_events(<<"u1">>,
+    [event(<<"shown">>, <<"cal|2|10">>), event(<<"confirm">>, <<"cal|2|10">>)]),
+  {ok, 1} = logic_ai_metrics:record_events(<<"u1">>, [event(<<"shown">>, <<"cal|2|10">>)]),
+  [Row] = mnesia:dirty_match_object(#ai_hint_metric{
+    id = {<<"u1">>, '_', <<"cal|2|10">>, <<"shown">>}, _ = '_'}),
+  ?assertEqual(2, Row#ai_hint_metric.count),
+  [_] = mnesia:dirty_match_object(#ai_hint_metric{
+    id = {<<"u1">>, '_', <<"cal|2|10">>, <<"confirm">>}, _ = '_'}).
+
+test_batch_limit() ->
+  Events = [event(<<"shown">>, iolist_to_binary(["p", integer_to_list(N)]))
+            || N <- lists:seq(1, 21)],
+  ?assertEqual({error, invalid_body}, logic_ai_metrics:record_events(<<"u1">>, Events)).
+
+test_summary() ->
+  {ok, _} = logic_ai_metrics:record_events(<<"u1">>,
+    [event(<<"shown">>, <<"a">>), event(<<"confirm">>, <<"a">>),
+     event(<<"confirm">>, <<"a">>), event(<<"dismiss">>, <<"b">>)]),
+  {ok, _} = logic_ai_metrics:record_events(<<"u2">>,
+    [event(<<"shown">>, <<"a">>), event(<<"confirm">>, <<"a">>)]),
+  S = logic_ai_metrics:summary(),
+  ?assertEqual(#{<<"shown">> => 2, <<"confirm">> => 3, <<"dismiss">> => 1},
+    maps:from_list(maps:to_list(maps:get(<<"by_kind">>, S)))),
+  ?assertEqual(2, maps:get(<<"active_users_30d">>, S)),
+  ?assertEqual(1, maps:get(<<"users_with_confirms_ge2_30d">>, S)),
+  ?assertEqual(0.5, maps:get(<<"gate_ratio_30d">>, S)),
+  [Top | _] = maps:get(<<"top_patterns_by_confirm">>, S),
+  ?assertEqual(<<"a">>, maps:get(<<"pattern">>, Top)),
+  ?assertEqual(3, maps:get(<<"confirms">>, Top)).

test/unit/migration_engine_tests.erl

@@ -19,7 +19,8 @@
   "20260815200000_push_subscription",
   "20260815220000_calendar_share_invite",
   "20260816180000_auth_session_device",
-  "20260817140000_month_snapshot"
+  "20260817140000_month_snapshot",
+  "20260820180000_ai_hint_metric"
 ]).
 
 setup() ->