feat(dashboard): console phase 2 - self-hosted basemap, basin stations, markers

- Basemap: src/static/basemap/ping-basin.pmtiles, a Protomaps extract of the
  Ping basin (zoom 0-12, 15 MB, OpenStreetMap data), drawn by
  protomaps-leaflet 5.1.0 (unpkg, SRI) in its light/dark style with labels in
  the page language. It replaces the dimmed OSM raster tiles, whose baked-in
  labels were the noisiest part of the screen; OSM stays as the fallback.
  The browser reads the file with range requests (ServeDir answers 206;
  dev_proxy.py now does too). The map stays within the basin.
- Basin stations: a second list next to the RID gauges and a map layer of
  diamonds, from /api/hii/waterlevel/latest (falling back to
  /sensors/thaiwater), coloured by ThaiWater's bank-height classes (over the
  bank = danger, 70-100 % = watch). Gauges RID already lists appear once.
  The panel shows level (m MSL), % of bank height, distance to and height of
  the bank top, gauge reading and agency; selection in the URL (#hii-<id>).
- custom-markers.json as pins from zoom 12, with the flood zone they are in.

Refresh instructions for the basemap in src/static/basemap/README.md.

docs/DASHBOARD_REDESIGN.md

@@ -1,6 +1,6 @@
 # Dashboard redesign: the console
 
-Status: **phase 1 done** (2026-10-19). The new dashboard is built next to the current
+Status: **phase 2 done** (2026-10-19). The new dashboard is built next to the current
 one and replaces it in phase 4.
 
 - **Preview:** <https://water.buildfor.life/static/console.html>, after `git pull` on the
@@ -50,9 +50,9 @@ One screen, no page scroll on a desktop:
 | Area | Content |
 |---|---|
 | Top bar | brand · **Chiang Mai verdict** (P.1 level + 24 h forecast, always visible, click selects P.1) · gauges reporting · highest 24 h flood chance · data age · EN/ไทย · light/dark · Get alerts |
-| Left | gauge list: status bar, code, name, margin to the warning level, 72 h sparkline, level and 6 h change; filter; sort by river order, closest to the warning level, rising; status legend |
-| Centre | map: Ping mainstem and tributaries, gauges coloured by status with code + level labels, layers Rain 24 h and Flood zones, one legend |
-| Right | selected gauge: level, 6 h change, discharge, warning/danger level with margins, capacity; level scale with now and 24 h peak; 72 h chart with the forecast peaks; forecast table (peak, chance of warning/danger at 6/12/24 h, model, issue time, disclaimer); for P.1 the seven inundation stages and the zones toggle; data links |
+| Left | two lists: **RID gauges** (status bar, code, name, margin to the warning level, 72 h sparkline, level and 6 h change; sort by river order, closest to the warning level, rising) and **Basin stations** (ThaiWater/HII: % of bank height, river and agency; sort fullest first or by name); filter; legend |
+| Centre | map on a self-hosted vector basemap (labels in the page language): Ping mainstem and tributaries, gauges coloured by status with code + level labels, layers Basin stations (diamonds), Rain 24 h and Flood zones, the team's markers from zoom 12, one legend |
+| Right | selected RID gauge: level, 6 h change, discharge, warning/danger level with margins, capacity; level scale with now and 24 h peak; 72 h chart with the forecast peaks; forecast table (peak, chance of warning/danger at 6/12/24 h, model, issue time, disclaimer); for P.1 the seven inundation stages and the zones toggle; data links. A basin station shows level (m MSL), % of bank height with ThaiWater's class, distance to and height of the bank top, gauge reading, agency (latest reading only: no history is kept for them) |
 | Status bar | data credits, API, source code |
 
 **Narrower screens:**
@@ -63,7 +63,7 @@ One screen, no page scroll on a desktop:
 | < 860 px | One column: verdict, map, list, panel |
 
 **Behaviour:**
-- Selection is in the URL (`#P.84`).
+- Selection is in the URL (`#P.84`, `#hii-1198299`); opening a basin station switches to its list.
 - Arrow keys move through the list.
 - Data refreshes every 5 minutes.
 
@@ -81,8 +81,8 @@ One screen, no page scroll on a desktop:
 | `refresh-button` | Removed: refresh every 5 min, age in the top bar | 1 |
 | `lang-toggle`, `theme-toggle` | EN / ไทย segmented control, icon button | 1 |
 | `error`, `loading` | Map overlay with retry; "Loading" in the list | 1 |
-| `thaiwater-sensors`, `sensors-*` | List tab + map layer | 2 |
-| custom markers | Map layer | 2 |
+| `thaiwater-sensors`, `sensors-*` | Basin stations list + map layer | 2 |
+| custom markers | Pins from zoom 12, popup with their flood zone | 2 |
 | `history-card`, `history-*` | Panel history with ranges | 3 |
 | `skill-panel`, `skill-*` | Panel section for P.1 | 3 |
 | `db-stats`, `db-*` | Status-bar popover | 3 |
@@ -109,6 +109,8 @@ One screen, no page scroll on a desktop:
 - **Discharge:** comes with RID's report. When the newest hour is a level-only reading, the panel shows the last RID discharge with its time ("at 14:00").
 - **Rain layer:** off by default unless any station has heavy rain (> 35 mm / 24 h); an explicit choice is remembered.
 - **Flood zones:** shown automatically while P.1 is at or above a stage, unless hidden by the user.
+- **Basin stations:** ThaiWater's classes for the level as a share of the bank height (critically low ≤ 10 %, low ≤ 30 %, normal ≤ 70 %, high ≤ 100 %, over the bank). On the map and in the list over the bank is danger, high is watch, the rest normal; no data after 24 h. Gauges RID already lists are shown once, as RID gauges. The layer is off until the list is opened or the button pressed.
+- **Basemap:** `src/static/basemap/ping-basin.pmtiles`, a Protomaps extract (bbox 97.85–99.95 E, 16.85–20.2 N, zoom 0–12, 15 MB, OpenStreetMap data), drawn by protomaps-leaflet 5.1.0 in its `light`/`dark` style with `name:th`/`name:en` labels. Refresh instructions in `src/static/basemap/README.md`. The map cannot be panned far outside the basin. OSM raster tiles are the fallback if the renderer does not load.
 
 ## Phases
 
@@ -121,13 +123,11 @@ Each phase is one commit, checked with screenshots: 1440, 1100 and 390 px; light
    - Station panel (readings, scale, 72 h chart, forecast table, P.1 stages).
    - Alerts drawer (ntfy topics); URL selection; 5-minute refresh.
    - `tests/test_console.py`; `dev_proxy.py` serves `src/static` with proper content types.
-2. **Map and basin.**
-   - **Basemap:** a self-hosted Protomaps extract of the Ping basin (PMTiles in `src/static/`, labels in Thai or English following the page language, light/dark themes). This replaces the dimmed OSM raster tiles, whose baked-in labels are the noisiest part of the screen.
-   - **Server:** check that ServeDir answers HTTP range requests (PMTiles needs them); add range support to `dev_proxy.py`.
-   - **ThaiWater/HII stations:**
-     - A tab in the list.
-     - A map layer: % of bank height, `/api/hii/waterlevel/latest`, falling back to `/sensors/thaiwater`.
-   - **Custom markers:** `custom-markers.json`, with their flood-zone popup.
+2. **Done — Map and basin.**
+   - **Basemap:** the self-hosted Protomaps extract replaces the dimmed OSM raster tiles, whose baked-in labels were the noisiest part of the screen. Labels follow the page language; light and dark styles.
+   - **Server:** ServeDir answers HTTP range requests (checked: 206); `dev_proxy.py` now does too.
+   - **ThaiWater/HII stations:** the Basin stations list and map layer, from `/api/hii/waterlevel/latest`, falling back to `/sensors/thaiwater`.
+   - **Custom markers:** `custom-markers.json` as pins, with their flood-zone popup.
 3. **Station depth.**
    - **History in the panel:** range 24 h / 7 d / 30 d / 90 d / all / custom dates, level and discharge, issued 24 h forecasts overlaid, flood bands; Chart.js or SVG.
    - **P.1 forecast skill** ("Is the model getting better?") as a panel section, from `/api/forecast/skill`.