feat(infra): implement batch transformation layer and comprehensive documentation

Add batch ETL pipeline with ODS→DDS→DM transformation jobs and scripts.
Create DDL infrastructure with automated database schema application.
Update Makefile with transform target for executing batch processes.
Rewrite README with complete Russian documentation including architecture
diagrams, quick start guide, and data flow visualization.

ddl/40_dm.sql

@@ -0,0 +1,117 @@
+-- DM layer: Data Marts for BI (Superset)
+-- Views for enriched data and pre-computed aggregations
+
+-- Main enriched view: event + click context
+CREATE VIEW IF NOT EXISTS dm.v_events_enriched AS
+SELECT
+    e.event_id,
+    e.event_ts,
+    e.event_date,
+    e.event_type,
+    e.click_id,
+    e.page_url,
+    e.page_url_path,
+    e.referer_url,
+    e.referer_medium,
+    e.utm_medium,
+    e.utm_source,
+    e.utm_content,
+    e.utm_campaign,
+    e.browser_name,
+    e.browser_language,
+    e.browser_user_agent,
+    c.user_domain_id,
+    c.user_custom_id,
+    c.device_type,
+    c.device_is_mobile,
+    c.os_name,
+    c.os_timezone,
+    c.geo_country,
+    c.geo_region_name,
+    c.geo_timezone,
+    c.geo_latitude,
+    c.geo_longitude,
+    c.ip_address,
+    e.dds_update_ts,
+    arrayConcat(e.ods_parse_errors, c.ods_parse_errors) AS parse_errors
+FROM dds.event AS e
+LEFT JOIN dds.click AS c ON c.click_id = e.click_id;
+
+-- Daily traffic aggregation
+CREATE VIEW IF NOT EXISTS dm.v_daily_traffic AS
+SELECT
+    event_date,
+    geo_country,
+    device_type,
+    browser_name,
+    utm_source,
+    utm_medium,
+    count() AS events,
+    uniqExact(click_id) AS uniq_clicks,
+    uniqExact(user_domain_id) AS uniq_users
+FROM dm.v_events_enriched
+WHERE event_ts IS NOT NULL
+GROUP BY
+    event_date,
+    geo_country,
+    device_type,
+    browser_name,
+    utm_source,
+    utm_medium;
+
+-- Top pages daily
+CREATE VIEW IF NOT EXISTS dm.v_top_pages_daily AS
+SELECT
+    event_date,
+    page_url_path,
+    count() AS pageviews,
+    uniqExact(click_id) AS uniq_clicks
+FROM dm.v_events_enriched
+WHERE event_type = 'pageview'
+GROUP BY event_date, page_url_path;
+
+-- Data Quality errors daily
+CREATE VIEW IF NOT EXISTS dm.v_dq_errors_daily AS
+SELECT
+    event_date,
+    arrayJoin(parse_errors) AS error_code,
+    count() AS rows_cnt
+FROM dm.v_events_enriched
+WHERE length(parse_errors) > 0
+GROUP BY event_date, error_code;
+
+-- User sessions overview (approximate, by click_id within 30min windows)
+CREATE VIEW IF NOT EXISTS dm.v_session_overview AS
+SELECT
+    event_date,
+    user_domain_id,
+    click_id,
+    min(event_ts) AS session_start,
+    max(event_ts) AS session_end,
+    date_diff('minute', min(event_ts), max(event_ts)) AS session_duration_min,
+    count() AS events_count,
+    arrayDistinct(groupArray(page_url_path)) AS pages_visited,
+    arrayDistinct(groupArray(geo_country)) AS countries,
+    arrayDistinct(groupArray(device_type)) AS devices,
+    groupArraySample(1, 1919)(utm_source)[1] AS utm_source_last,
+    groupArraySample(1, 1919)(utm_medium)[1] AS utm_medium_last
+FROM dm.v_events_enriched
+WHERE user_domain_id IS NOT NULL
+GROUP BY event_date, user_domain_id, click_id;
+
+-- UTM effectiveness (for marketing analysis)
+CREATE VIEW IF NOT EXISTS dm.v_utm_effectiveness AS
+SELECT
+    event_date,
+    utm_source,
+    utm_medium,
+    utm_campaign,
+    count() AS clicks,
+    uniqExact(user_domain_id) AS uniq_users,
+    uniqExact(click_id) AS uniq_sessions,
+    countIf(event_type = 'pageview') AS pageviews,
+    countIf(event_type = 'purchase') AS purchases,
+    countIf(event_type = 'add_to_cart') AS add_to_carts
+FROM dm.v_events_enriched
+WHERE utm_source IS NOT NULL OR utm_medium IS NOT NULL
+GROUP BY event_date, utm_source, utm_medium, utm_campaign;