docs: document filters (plate A→Z, cost centre, assigned city, time) + zoom-scaled markers

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -3,12 +3,19 @@
 A single-file map console that **merges live vehicle positions and historical
 trips** into one view for the Fireside Communications / Tracksolid fleet.
 
-- Land on the **live fleet** (cost-centre-coloured pins, heading arrows, hover
+- Land on the **live fleet** — cost-centre-coloured pins with a heading arrow, the
-  popups with reverse-geocoded address).
+  plate tail below, and a hover popup (status, driver, reverse-geocoded address,
-- Pick a vehicle (click its dot → **Show trips**, or the plate dropdown) or apply
+  heading, odometer, last fix, source). Markers **scale with the zoom level**.
-  **cost centre + time period** → the map switches to **seq-coloured trip routes**
+- **Filters** (bottom-right card) apply to the live map *instantly*:
-  with start/end markers and a click-to-animate replay.
+  - **Number plate** — multi-select, sorted A→Z; picking a vehicle auto-fills its
-- The **● Live** pill returns to the live snapshot.
+    cost centre + city.
+  - **Cost centre** and **Assigned city** — narrow the live fleet (and the KPI bar
+    recomputes to match).
+  - **Time** (Today / 1 week / 1 month / Custom) — applies to **trips**, not live.
+- Drill into history: click a vehicle's dot → **Show trips**, or set
+  plate / cost centre / city + period and hit **Show trips** for a fleet-wide pull.
+  The map switches to **seq-coloured trip routes** with start/end markers and a
+  click-to-animate replay; the **● Live** pill returns to the live snapshot.
 
 Live: <https://fleetnow.rahamafresh.com>