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_dashboard.py

@@ -1,23 +1,53 @@
+import re
 from pathlib import Path
 
-
 DASHBOARD_PATH = Path(__file__).parents[1] / "src" / "static" / "dashboard.html"
+ROUTER_PATH = (
+    Path(__file__).parents[1] / "rust" / "collector" / "src" / "web" / "mod.rs"
+)
+
+
+def _rust_routes() -> set:
+    """Paths the website serves (ping-collector's axum router)."""
+    source = ROUTER_PATH.read_text(encoding="utf-8")
+    return set(re.findall(r'\.route\(\s*"([^"]+)"', source))
+
+
+def test_every_api_path_the_dashboard_fetches_is_served():
+    html = DASHBOARD_PATH.read_text(encoding="utf-8")
+    routes = _rust_routes()
+    patterns = [
+        re.compile("^" + re.sub(r"\\\{[^}]+\\\}", "[^/]+", re.escape(r)) + "$")
+        for r in routes
+    ]
+    fetched = set(re.findall(r"fetch\(\s*[`'\"](/[^`'\"?$]*)", html))
+    assert fetched, "no fetch() calls found"
+    missing = [
+        path
+        for path in fetched
+        if not path.startswith("/static/")
+        and not any(p.match(path.rstrip("/") or "/") for p in patterns)
+        and not any(r.startswith(path) for r in routes)
+    ]
+    assert not missing, f"dashboard fetches paths the server does not route: {missing}"
 
 
 def test_dashboard_contains_live_map_and_flow_visualization():
     html = DASHBOARD_PATH.read_text(encoding="utf-8")
 
-    assert "id=\"station-map\"" in html
-    assert "id=\"river-flow\"" in html
+    assert 'id="station-map"' in html
+    assert 'id="river-flow"' in html
     assert "fetch('/stations')" in html or 'fetch("/stations")' in html
-    assert "fetch('/measurements/latest" in html or 'fetch(\"/measurements/latest' in html
+    assert (
+        "fetch('/measurements/latest" in html or 'fetch("/measurements/latest' in html
+    )
     assert "leaflet" in html.lower()
 
 
 def _body(html: str) -> str:
     """Markup only. The STRINGS table repeats every English phrase, so a
     whole-file search would pass even if an element were deleted."""
-    return html[html.index("<body>"):html.index("<script src=")]
+    return html[html.index("<body>") : html.index("<script src=")]
 
 
 def test_dashboard_explains_flow_legend_and_refresh():
@@ -57,13 +87,14 @@ def test_dashboard_has_seo_and_indexing_files():
 
     robots = (static_dir / "robots.txt").read_text(encoding="utf-8")
     assert "Sitemap: https://water.buildfor.life/sitemap.xml" in robots
-    assert "<loc>https://water.buildfor.life/</loc>" in (static_dir / "sitemap.xml").read_text(encoding="utf-8")
-    assert "Ping River Live Monitor" in (static_dir / "llms.txt").read_text(encoding="utf-8")
+    assert "<loc>https://water.buildfor.life/</loc>" in (
+        static_dir / "sitemap.xml"
+    ).read_text(encoding="utf-8")
+    assert "Ping River Live Monitor" in (static_dir / "llms.txt").read_text(
+        encoding="utf-8"
+    )
 
-    from src import web_api
-
-    routes = {route.path for route in web_api.app.routes}
-    assert {"/robots.txt", "/llms.txt", "/sitemap.xml"} <= routes
+    assert {"/robots.txt", "/llms.txt", "/sitemap.xml"} <= _rust_routes()
 
 
 def test_dashboard_shows_hii_rainfall_layer():
@@ -124,7 +155,9 @@ def test_dashboard_translations_cover_both_languages():
     missing_th = tables["en"] - tables["th"]
     missing_en = tables["th"] - tables["en"]
     assert not missing_th, f"keys missing a Thai translation: {sorted(missing_th)}"
-    assert not missing_en, f"Thai-only keys with no English fallback: {sorted(missing_en)}"
+    assert (
+        not missing_en
+    ), f"Thai-only keys with no English fallback: {sorted(missing_en)}"
 
 
 def test_dashboard_i18n_markup_keys_exist():
@@ -156,7 +189,7 @@ def test_dashboard_translates_user_visible_aria_labels():
     body = _body(html)
     for match in re.finditer(r'<[^>]*\saria-label="[^"]+"[^>]*>', body):
         tag = match.group(0)
-        if "data-i18n-aria" in tag or "id=\"lang-toggle\"" in tag:
+        if "data-i18n-aria" in tag or 'id="lang-toggle"' in tag:
             continue  # the toggle sets its own label per language in JS
         raise AssertionError(f"aria-label without a translation key: {tag[:120]}")