chore: remove the Python service; Python is the training stack only

Phase 4 of docs/RUST_REWRITE.md. Since 2026-10-18 ping-collector (rust/)
collects, forecasts, notifies (ntfy + Matrix) and serves the website/API;
nothing in production ran the Python service code any more.

Removed (~17k lines): the FastAPI app (web_api, schemas, health_check,
metrics, postgres_history, forecast_history, thaiwater), the Python RID
collector and CLI (water_scraper_v3, main, run.py), the notifier and Matrix
alerting (notify, alerting), the multi-backend adapters (SQLite, MySQL,
InfluxDB, VictoriaMetrics) with demo databases, models/validators/exceptions/
logging/rate limiter, ml/skill.py (served by Rust now), the migration tooling
(api_parity, collector_parity, e2e_notify, install_collector.sh,
gen_notify_cases.py, spikes/rust-forecast), Docker/compose/Grafana files,
sql/, the release workflow and the docs for all of that. Their tests went
with them.

Kept in Python: src/ml (training, evaluation harness, export; predict.py as
the reference the Rust forecaster is tested against), the HII and RID-dam
clients/stores for the archive backfills (their live collectors removed),
the backfill scripts, retrain.sh + timer, forecast_parity.py.

- PostgreSQL only: src/config.py is database_url() from POSTGRES_* / .env;
  the stores lost their sqlite/mysql branches (and the 2026-08 column
  migration). The database tests run against a throwaway schema from
  TEST_DATABASE_URL (tests/conftest.py pg_url, skipped without it), as the
  Rust tests do; CI gets a PostgreSQL service. 100 tests (66 without a DB).
- The notifier settings moved from src/notify.py into src/ml/export.py;
  flood_config.json regenerates byte-identical.
- tests/test_dashboard.py checks every path the dashboard fetches against
  ping-collector's router.
- Dependencies: fastapi, uvicorn, pydantic, influxdb, pymysql, psutil,
  schedule, sphinx, pyinstaller, mypy, pytest-asyncio dropped; python-dotenv
  1.1.1 explicit (it came in through uvicorn[standard]).
- Formatting contract extended to scripts/ and tests/ (reformatted once).
- scripts/install.sh is the one installer (fresh host or update, in place in
  a checkout without touching its ownership): binary, units, uv sync, .env
  defaults, removes the retired water-monitor.service and any old
  --alert-check cron job, dry run + forecast check, restart, readiness wait.
- Docs, CLAUDE.md, CONTRIBUTING.md, .env.example, Makefile, unit comments
  and Rust doc comments updated to the Rust service.

tests/test_rid_reservoir.py

@@ -1,4 +1,4 @@
-"""Tests for the RID large-dam daily collector (parsing + persistence)."""
+"""Tests for the RID large-dam client/store/backfill (parsing + persistence)."""
 
 import datetime
 
@@ -6,7 +6,6 @@ import pytest
 
 from src.rid_reservoir import (
     MAE_NGAT_DAM_ID,
-    RidReservoirCollector,
     RidReservoirStore,
     backfill,
     backfill_dam,
@@ -131,8 +130,9 @@ class FakeRangeClient:
             start + datetime.timedelta(days=i) for i in range((end - start).days + 1)
         ]
         return parse_dam_range_records(
-            _range_payload(rows=[_range_row(d.isoformat()) for d in days
-                                 if d not in self.gaps])
+            _range_payload(
+                rows=[_range_row(d.isoformat()) for d in days if d not in self.gaps]
+            )
         )
 
 
@@ -177,7 +177,9 @@ class TestParsing:
         )
 
     def test_parse_dam_range_zero_level_is_missing_not_a_reading(self):
-        payload = _range_payload(rows=[_range_row("2024-09-24", DMD_ULevel_curr="0.00")])
+        payload = _range_payload(
+            rows=[_range_row("2024-09-24", DMD_ULevel_curr="0.00")]
+        )
         assert parse_dam_range_records(payload)[0]["level_msl"] is None
 
     def test_parse_dam_range_skips_broken_rows(self):
@@ -196,14 +198,11 @@ class TestParsing:
 
 class TestStore:
     @pytest.fixture
-    def store(self, tmp_path):
-        store = RidReservoirStore(f"sqlite:///{tmp_path}/rsv_test.db", "sqlite")
+    def store(self, pg_url):
+        store = RidReservoirStore(pg_url)
         assert store.connect()
-        return store
-
-    def test_rejects_non_sql(self):
-        with pytest.raises(ValueError):
-            RidReservoirStore("http://localhost:8428", "victoriametrics")
+        yield store
+        store.engine.dispose()
 
     def test_roundtrip_and_upsert(self, store):
         records = parse_dam_records(_dams_payload())
@@ -269,8 +268,11 @@ class TestStore:
         date = "2026-08-13"
         assert store.save(parse_dam_range_records(_range_payload((date,)))) == 1
         # api/dams has no level column at all; its rewrite must not clear one
-        dams_row = [r for r in parse_dam_records(_dams_payload(date))
-                    if r["dam_id"] == MAE_NGAT_DAM_ID]
+        dams_row = [
+            r
+            for r in parse_dam_records(_dams_payload(date))
+            if r["dam_id"] == MAE_NGAT_DAM_ID
+        ]
         assert dams_row[0]["level_msl"] is None
         store.save(dams_row)
         from sqlalchemy import text
@@ -315,27 +317,15 @@ class TestStore:
         assert row[2] == "เหนือ"
 
 
-class TestCollectorAndBackfill:
-    def test_run_cycle_today_and_yesterday(self, tmp_path):
-        collector = RidReservoirCollector(
-            {"type": "sqlite", "connection_string": f"sqlite:///{tmp_path}/c.db"},
-            client=FakeClient(),
-        )
-        saved = collector.run_cycle()
-        assert saved == 4  # 2 dams x (today + yesterday)
-        assert collector.client.calls[0] is None  # today via empty date
-
-    def test_run_cycle_survives_fetch_failure(self, tmp_path):
-        yesterday = datetime.date.today() - datetime.timedelta(days=1)
-        collector = RidReservoirCollector(
-            {"type": "sqlite", "connection_string": f"sqlite:///{tmp_path}/f.db"},
-            client=FakeClient(fail_dates={yesterday}),
-        )
-        assert collector.run_cycle() == 2  # today only
-
-    def test_backfill_range(self, tmp_path):
-        store = RidReservoirStore(f"sqlite:///{tmp_path}/b.db", "sqlite")
+class TestBackfill:
+    @pytest.fixture
+    def store(self, pg_url):
+        store = RidReservoirStore(pg_url)
         assert store.connect()
+        yield store
+        store.engine.dispose()
+
+    def test_backfill_range(self, store):
         client = FakeClient()
         saved = backfill(
             store,
@@ -351,9 +341,7 @@ class TestCollectorAndBackfill:
             datetime.date(2024, 9, 26),
         ]
 
-    def test_backfill_skips_present_days_so_reruns_repair_holes(self, tmp_path):
-        store = RidReservoirStore(f"sqlite:///{tmp_path}/skip.db", "sqlite")
-        assert store.connect()
+    def test_backfill_skips_present_days_so_reruns_repair_holes(self, store):
         # Day 25 already stored (e.g. by the live collector)
         store.save(parse_dam_records(_dams_payload("2024-09-25")))
         client = FakeClient()
@@ -370,9 +358,7 @@ class TestCollectorAndBackfill:
         ]
         assert saved == 4
 
-    def test_backfill_aborts_when_db_saves_nothing(self, tmp_path, monkeypatch):
-        store = RidReservoirStore(f"sqlite:///{tmp_path}/deaddb.db", "sqlite")
-        assert store.connect()
+    def test_backfill_aborts_when_db_saves_nothing(self, store, monkeypatch):
         monkeypatch.setattr(store, "save", lambda records: 0)  # broken DB
         client = FakeClient()
         backfill(
@@ -384,9 +370,7 @@ class TestCollectorAndBackfill:
         )
         assert len(client.calls) == 5  # aborted, not one request per day
 
-    def test_backfill_aborts_after_consecutive_failures(self, tmp_path):
-        store = RidReservoirStore(f"sqlite:///{tmp_path}/a.db", "sqlite")
-        assert store.connect()
+    def test_backfill_aborts_after_consecutive_failures(self, store):
         start = datetime.date(2024, 1, 1)
         fail_dates = {start + datetime.timedelta(days=i) for i in range(2, 30)}
         client = FakeClient(fail_dates=fail_dates)
@@ -403,10 +387,11 @@ class TestCollectorAndBackfill:
 
 class TestBackfillDam:
     @pytest.fixture
-    def store(self, tmp_path):
-        store = RidReservoirStore(f"sqlite:///{tmp_path}/range.db", "sqlite")
+    def store(self, pg_url):
+        store = RidReservoirStore(pg_url)
         assert store.connect()
-        return store
+        yield store
+        store.engine.dispose()
 
     def test_whole_range_in_one_request(self, store):
         client = FakeRangeClient()
@@ -451,9 +436,7 @@ class TestBackfillDam:
         assert saved == 4  # the day the source never published stays absent
         assert store.present_dates(
             datetime.date(2024, 1, 1), datetime.date(2024, 1, 5)
-        ) == {
-            datetime.date(2024, 1, d) for d in (1, 2, 4, 5)
-        }
+        ) == {datetime.date(2024, 1, d) for d in (1, 2, 4, 5)}
 
     def test_stored_days_are_skipped_and_whole_chunks_cost_no_request(self, store):
         client = FakeRangeClient()