feat(dashboard): console phase 4 - 2024 replay, simulation, replaces the old page

The console is now the dashboard at / (src/static/dashboard.html); the old
page and console.html are gone.

- Replay of the October 2024 flood (flood-2024-all.json): the page's clock,
  verdict, list, markers, flood zones and panel follow the replay; the panel
  charts the season on fixed axes with the 2024 model's 24 h peak. Hourly
  while the model alerts or P.1 is above 3.50 m, faster through quiet days;
  pause and drag. Rain, basin stations and the 5-minute refresh are off
  during the replay (today's data).
- ?demo_level= and ?demo_rise= simulate P.1. A violet REPLAY / amber
  SIMULATION bar, the top bar's KPI and the P.1 panel say so; the mode is
  drawn from state.mode alone, so a refresh or language switch cannot
  relabel either as live.
- History: rows without discharge_percent are ThaiWater's copy of the gauge
  (night hours RID publishes late), with a different rating (P.1: 26 against
  RID's 54 m3/s); their discharge is not drawn for gauges with RID discharge.
  The discharge strip has headroom so its label stays clear of the line.
- Swap: the old page's title, description, Open Graph and JSON-LD tags; no
  noindex; tests/test_dashboard.py = console tests + the old checks that
  still apply (one P.1 level, SEO files) + a replay/simulation labelling test.
- Docs: README screenshot (docs/img/dashboard.jpg, replacing two unused
  images), CLAUDE.md, CONTRIBUTING.md, FLOOD_FORECASTING.md (where the model
  shows), DASHBOARD_REDESIGN.md (phase 4 done, mode rules).

Deploy needs a restart: the server reads dashboard.html at start.

CLAUDE.md

@@ -30,12 +30,12 @@ plus the monthly `water-monitor-retrain.timer` (Python, `.venv`, uv-managed). Up
 - No `git add -A`: zero-byte shell-accident files (`#`, `$(wc`, ...) have been committed
   before. Stage files by name.
 - 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). 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`.
+- The dashboard is a single file, `src/static/dashboard.html` (design and rules in
+  docs/DASHBOARD_REDESIGN.md), EN + TH via the `t()` table: every user-visible string
+  needs both languages, Thai is the default, no emoji. Every path it fetches must be a
+  route in `rust/collector/src/web/mod.rs` (tests/test_dashboard.py checks). A replay or
+  a simulation must never be shown as live data. Preview it against production with
+  `uv run python scripts/dev_proxy.py`; the server reads it at start (restart).
 - 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