feat: Add comprehensive test suite and cleanup step

- Split validation into 4 granular CI steps (Config, Timescale, Vector, Hybrid)
- Added cleanup step for Docker images in CI
- Created SQL test scripts in tests/ for robustness

tests/test-2-timescale.sql

@@ -0,0 +1,31 @@
+-- Test 2: TimescaleDB
+\set ON_ERROR_STOP on
+
+DROP TABLE IF EXISTS sensors CASCADE;
+
+CREATE TABLE sensors (
+    time TIMESTAMPTZ NOT NULL,
+    sensor_id INTEGER,
+    temperature DOUBLE PRECISION
+);
+
+-- Convert to hypertable
+SELECT create_hypertable('sensors', 'time');
+
+-- Insert data
+INSERT INTO sensors (time, sensor_id, temperature) VALUES 
+    (NOW(), 1, 20.0), 
+    (NOW() + INTERVAL '1 hour', 1, 22.0);
+
+-- Query data
+DO $$
+DECLARE
+    count int;
+BEGIN
+    SELECT count(*) INTO count FROM sensors;
+    IF count != 2 THEN
+        RAISE EXCEPTION 'Hypertable insert failed';
+    END IF;
+    RAISE NOTICE 'TimescaleDB Check: OK';
+END
+$$;