feat(dashboard): the console, phase 1 of the redesign (preview at /static/console.html)

The user chose direction B of the redesign: a full-screen operations console.
It is built next to the current dashboard, served by ServeDir at
/static/console.html (noindex, links back to /), and replaces dashboard.html
once it covers every feature (docs/DASHBOARD_REDESIGN.md, phase 4).

Phase 1:
- top bar: the Chiang Mai verdict (P.1 level + 24 h forecast, the current
  dashboard's rule), gauges reporting, highest 24 h flood chance, data age
  ("overnight pause" instead of "stale" during RID's nightly gap, as in the
  notifier), EN/TH, light/dark (dark default), Get alerts
- gauge list: one status rule for list, map and panel (normal, watch within
  0.5 m or >= 25 % chance, warning, danger, no data), margin to the warning
  level, 72 h sparkline, 6 h change; filter; sort by river order, closest to
  the warning level, rising; arrow keys
- map: Ping mainstem and tributaries, status markers with code + level,
  layers Rain 24 h (on by default only with heavy rain) and Flood zones
  (auto-shown while P.1 is at a stage), one legend
- station panel: level, change, discharge (last RID value when the newest
  hour is level-only), warning/danger levels with margins, capacity, level
  scale with now and 24 h peak, 72 h chart with the forecast peaks, forecast
  table with the model and issue time, the P.1 inundation stages, data links
- alerts drawer with the ntfy topics; selection in the URL (#P.84); refresh
  every 5 minutes
- Inter and Noto Sans Thai self-hosted (src/static/fonts, 75 KB, OFL), no
  emoji, Thai first, Bangkok time

tests/test_console.py: routed fetch paths, EN/TH parity, translated aria
labels, no emoji, fonts and licences, noindex. dev_proxy.py serves
src/static with real content types (it sent HTML as octet-stream).

CLAUDE.md

@@ -32,7 +32,10 @@ plus the monthly `water-monitor-retrain.timer` (Python, `.venv`, uv-managed). Up
 - Do not add Co-Authored-By trailers.
 - The dashboard is a single file, `src/static/dashboard.html`, EN + TH via the `t()`
   table: every user-visible string needs both languages. Every path it fetches must be
-  a route in `rust/collector/src/web/mod.rs` (tests/test_dashboard.py checks).
+  a route in `rust/collector/src/web/mod.rs` (tests/test_dashboard.py checks). Its
+  replacement, the console (`src/static/console.html`, preview at /static/console.html,
+  plan in docs/DASHBOARD_REDESIGN.md), follows the same rules plus no emoji
+  (tests/test_console.py); preview it with `uv run python scripts/dev_proxy.py`.
 - Rust (`rust/`, see rust/README.md): `cargo fmt --all`, `cargo clippy --all-targets
   -- -D warnings`, `cargo test`; minimum version 1.88
   (`CARGO_TARGET_DIR=target/msrv cargo +1.88 check --all-targets --locked`). Read