devices: pool-of-spaces model — drop lane, per-relay direction

A parking lot is one pool of spaces with a flexible set of entry/exit
points — no "lane". Direction is a property of each RELAY inside an access
controller; readers/cameras bind to a controller relay and inherit it.

Schema:
- drop `lane` from ledger_events, device_events, sessions
- rename lane_devices -> devices (no lane/direction columns)
- access config.relays=[{relay,direction,button?}]; reader/camera
  config.controllerId+relay binding
- fresh 0000_baseline migration (history reset; dev data was throwaway)

Signed ledger:
- remove `lane` from canonicalize(); bump signer keyId sw-hmac-v1 -> v2
  (v1 events won't verify under v2 — intentional, gated per-event by keyId)

Server:
- new device-resolve.ts (replaces lane-map.ts): relayForButton,
  relayForDevice, firstRelayByDirection, devicesByDirection
- entry-flow: button terminal -> its relay; exit/permit: reader's bound
  relay; dispatcher resolves the bound relay + inherited direction
- camera snapshots fire by direction site-wide, async, never block open
- DeviceConfig widened to nested JSON for relays[]

Web:
- wizard: no lane selector; add controllers (relay map + entry-button
  terminal) first, then bind readers/cameras/printers to a controller relay

Wiki: new entry-exit-points.md (replaces lane-direction); reworked
entry-exit-readers, parking-session, first-run-setup, device-registry,
append-only-event-chain, device-events; removed stale lane/LaneMap mentions.

wiki/concepts/device-registry.md

@@ -10,7 +10,7 @@ updated: 2026-06-15
 How the system goes from "device-agnostic in principle" ([[device-adapter-pattern]]) to
 "**admin picks the device at setup**" in practice. A **registry** holds a catalog of supported
 **drivers**, grouped by category; the [[first-run-setup]] UI reads it so an
-operator can choose a device per lane and fill in its connection config.
+operator can choose a device and fill in its connection config.
 
 > Implementation-derived (from `packages/devices`), not the source doc.
 
@@ -33,10 +33,11 @@ driver; **no business-logic change** — this is the [[device-adapter-pattern]]
 
 ## Why a registry (not hard-coded wiring)
 
-- The admin chooses between **multiple devices per category** at install time, per lane
-  (mirrors the "mixable per lane" principle — see [[trust-boundary]], [[entry-exit-readers]]).
+- The admin chooses between **multiple devices per category** at install time
+  (a controller's relays mix entry/exit; readers bind to them — see [[entry-exit-points]],
+  [[trust-boundary]], [[entry-exit-readers]]).
 - Config is **validated against the driver's declared fields** before persisting.
-- Selections persist in the `lane_devices` table and drive runtime adapter construction.
+- Selections persist in the `devices` table and drive runtime adapter construction.
 - Drivers may optionally implement **[[device-discovery]]** (`discover()`), so the admin can scan
   the LAN instead of typing connection details — no current driver uses it (the UHPPOTE did,
   before removal; the [[dingtian-relay]] uses a fixed IP).