Drop .env handling, fix default dataset, update README

- Remove .env.example and its .gitignore entry; compose sets the
  dev credentials directly. Basic auth in the image is unchanged.
- Preselect the last dataset by name instead of by mtime, which is
  meaningless after a git checkout in CI
- README: Esc zoom reset, data update flow, data visibility note,
  runner image requirements, dev login for compose
- Remove duplicate data/history2.csv

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

data/history2.csv

@@ -1,71 +0,0 @@
-entity_id,state,last_changed
-binary_sensor.heatpump_compressor,on,2026-09-17T03:00:19.068Z
-binary_sensor.heatpump_compressor,off,2026-09-17T03:08:01.062Z
-binary_sensor.heatpump_compressor,on,2026-09-17T11:26:17.041Z
-binary_sensor.heatpump_compressor,off,2026-09-17T11:41:03.220Z
-binary_sensor.heatpump_compressor,on,2026-09-18T03:00:22.102Z
-binary_sensor.heatpump_compressor,off,2026-09-18T03:19:35.943Z
-binary_sensor.heatpump_compressor,on,2026-09-18T10:19:43.304Z
-binary_sensor.heatpump_compressor,off,2026-09-18T10:36:39.042Z
-binary_sensor.heatpump_compressor,on,2026-09-19T01:20:46.148Z
-binary_sensor.heatpump_compressor,off,2026-09-19T01:22:54.097Z
-binary_sensor.heatpump_compressor,on,2026-09-19T02:22:51.267Z
-binary_sensor.heatpump_compressor,off,2026-09-19T02:28:06.281Z
-binary_sensor.heatpump_compressor,on,2026-09-19T03:28:40.219Z
-binary_sensor.heatpump_compressor,off,2026-09-19T03:35:46.221Z
-binary_sensor.heatpump_compressor,on,2026-09-19T04:41:58.300Z
-binary_sensor.heatpump_compressor,off,2026-09-19T04:49:50.417Z
-binary_sensor.heatpump_compressor,on,2026-09-19T05:57:54.487Z
-binary_sensor.heatpump_compressor,off,2026-09-19T06:43:11.390Z
-binary_sensor.heatpump_compressor,on,2026-09-19T09:12:49.606Z
-binary_sensor.heatpump_compressor,off,2026-09-19T09:29:53.590Z
-binary_sensor.heatpump_compressor,on,2026-09-20T03:39:39.610Z
-binary_sensor.heatpump_compressor,off,2026-09-20T03:42:03.650Z
-binary_sensor.heatpump_compressor,on,2026-09-20T04:41:55.897Z
-binary_sensor.heatpump_compressor,off,2026-09-20T04:47:38.833Z
-binary_sensor.heatpump_compressor,on,2026-09-20T05:48:38.700Z
-binary_sensor.heatpump_compressor,off,2026-09-20T05:55:45.486Z
-binary_sensor.heatpump_compressor,on,2026-09-20T06:00:23.429Z
-binary_sensor.heatpump_compressor,off,2026-09-20T06:36:28.105Z
-binary_sensor.heatpump_compressor,on,2026-09-20T09:50:15.244Z
-binary_sensor.heatpump_compressor,off,2026-09-20T10:01:52.926Z
-binary_sensor.heatpump_compressor,on,2026-09-21T03:00:04.587Z
-binary_sensor.heatpump_compressor,off,2026-09-21T03:05:11.361Z
-binary_sensor.heatpump_compressor,unknown,2026-09-21T08:18:28.438Z
-binary_sensor.heatpump_compressor,off,2026-09-21T08:18:30.643Z
-binary_sensor.heatpump_compressor,on,2026-09-22T03:00:05.235Z
-binary_sensor.heatpump_compressor,off,2026-09-22T03:20:51.957Z
-binary_sensor.heatpump_compressor,on,2026-09-22T09:45:24.980Z
-binary_sensor.heatpump_compressor,off,2026-09-22T10:05:30.687Z
-binary_sensor.heatpump_compressor,on,2026-09-23T03:00:08.414Z
-binary_sensor.heatpump_compressor,off,2026-09-23T03:12:46.457Z
-binary_sensor.heatpump_compressor,on,2026-09-23T09:45:29.000Z
-binary_sensor.heatpump_compressor,off,2026-09-23T10:04:03.857Z
-binary_sensor.heatpump_compressor,on,2026-09-24T03:00:09.997Z
-binary_sensor.heatpump_compressor,off,2026-09-24T03:11:26.925Z
-binary_sensor.heatpump_compressor,on,2026-09-24T12:34:34.499Z
-binary_sensor.heatpump_compressor,off,2026-09-24T13:05:30.499Z
-binary_sensor.heatpump_compressor,on,2026-09-25T03:00:07.285Z
-binary_sensor.heatpump_compressor,off,2026-09-25T03:39:07.324Z
-binary_sensor.heatpump_compressor,unknown,2026-09-25T08:35:58.362Z
-binary_sensor.heatpump_compressor,off,2026-09-25T08:36:05.755Z
-binary_sensor.heatpump_compressor,unknown,2026-09-25T08:36:57.698Z
-binary_sensor.heatpump_compressor,off,2026-09-25T08:36:58.846Z
-binary_sensor.heatpump_compressor,unknown,2026-09-25T08:41:12.345Z
-binary_sensor.heatpump_compressor,off,2026-09-25T08:41:15.133Z
-binary_sensor.heatpump_compressor,on,2026-09-25T09:28:41.719Z
-binary_sensor.heatpump_compressor,off,2026-09-25T09:54:51.506Z
-binary_sensor.heatpump_compressor,on,2026-09-26T00:42:45.260Z
-binary_sensor.heatpump_compressor,off,2026-09-26T00:44:28.166Z
-binary_sensor.heatpump_compressor,on,2026-09-26T01:18:30.843Z
-binary_sensor.heatpump_compressor,off,2026-09-26T01:23:43.918Z
-binary_sensor.heatpump_compressor,on,2026-09-26T02:10:50.330Z
-binary_sensor.heatpump_compressor,off,2026-09-26T02:18:56.282Z
-binary_sensor.heatpump_compressor,on,2026-09-26T03:08:29.828Z
-binary_sensor.heatpump_compressor,off,2026-09-26T03:17:03.786Z
-binary_sensor.heatpump_compressor,on,2026-09-26T04:07:50.486Z
-binary_sensor.heatpump_compressor,off,2026-09-26T04:17:22.353Z
-binary_sensor.heatpump_compressor,on,2026-09-26T05:06:08.060Z
-binary_sensor.heatpump_compressor,off,2026-09-26T05:16:05.238Z
-binary_sensor.heatpump_compressor,on,2026-09-26T06:00:08.484Z
-binary_sensor.heatpump_compressor,off,2026-09-26T06:37:50.037Z