refactor(setup): unify controller I/O — event-driven relays[] + generic inputs[]

The controller new/edit modal hardcoded both its outputs and its inputs, so an
operator could neither add a generic event-driven relay nor a free-standing input
(e.g. a second radar at the exit). This unifies both into symmetric, first-class
lists. Behaviour for existing booths is unchanged (back-compat, no DB migration).

Outputs — one event→action relays[] list:
- A relay is "when EVENT X happens, do its action": entry/exit/both pulse a
  barrier; a new `radarAlert` event drives a non-barrier alert lamp (blink while
  its trigger input is active, SOLID once the camera confirms a car).
- Dropped the separate config.buttonLight block — the lamp is just a relays[] row
  with direction:"radarAlert" (triggerInput + blink cadence). `alertRelaysOf()`
  replaces `buttonLightOf()`; ButtonLightController keeps its proven 3-state
  machine (serialized UDP, fail-OFF, hot-reload), now keyed per controllerId:relay
  so several alert lamps on one controller run independently. Every barrier
  resolver skips radarAlert rows (no auto-open; barrier-not-a-door intact).

Inputs — one first-class config.inputs[] list (the twin of relays[]):
- Each row is { input, role, relay?, kind?, activeLow?, cooldownSec? } with a
  "+ Add input" button. role ∈ button | presence | alertTrigger; button/presence
  name the relay they serve. An exit radar is just another presence row.
- Keystone `inputsOf(row)`: returns config.inputs[] or SYNTHESIZES it from the
  legacy relays[].button/presenceInput/... fields, so relayForButton /
  relayForPresence resolve identically from either shape — zero-downtime, no
  migration. entry-flow.ts is unchanged (resolves through the same functions).
- Fixed a latent bug this exposed: the alert lamp's camera lock was hardcoded to
  the ENTRY camera. Added relays[].lockLane ("entry"|"exit", default entry); the
  lamp now locks on its own lane's camera, so an exit radar's lamp tracks the exit
  camera. button-light tracks both #entryBusy/#exitBusy.
- Driver: extracted activeLowFrom(config) — merges inputs[] activeLow, legacy
  relays[].presenceActiveLow, and the inputActiveLow escape hatch.

UI: the relay dropdown gained a "Radar alert" option (reveals trigger/lock/blink
inputs); InputEditor is rewritten to a generic list (role select folds loop/radar);
i18n sq+en kept at type-parity.

Tests: new device-resolve.test.ts (inputs[] resolution + legacy fallback identical
+ exit-radar resolves to the exit relay); button-light gains a two-independent-
alert-relays case and an exit-lamp lockLane case; access-dingtian gains
activeLowFrom cases. Full workspace build/lint/test green (i18n parity included).

Wiki + memory updated (button-light-indicator, entry-double-press, dingtian-relay).

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

wiki/concepts/button-light-indicator.md

@@ -1,46 +1,59 @@
 ---
 type: concept
-tags: [parking, device, indicator, radar, camera, aux-output, barrier-not-a-door]
+tags: [parking, device, indicator, radar, camera, aux-output, barrier-not-a-door, event-relay]
 sources: []
-updated: 2026-06-24
+updated: 2026-06-28
 status: settled
 ---
 
-# Button-light indicator (radar × camera disagreement lamp)
+# Alert relays (radar × camera disagreement lamp)
 
-The entry button has a **12 V light**. It is driven by the host on a **spare relay** of the
-[[dingtian-relay|Dingtian]] controller as a 3-state indicator that combines the **[[hikvision-radar|
-radar]]** input with the **camera "car in zone"** signal:
+A relay on the [[dingtian-relay|Dingtian]] controller is uniformly **"when EVENT X happens, do
+action Y"** — see [[entry-exit-points|relays carry an event]]. The barrier events (`entry`/`exit`/
+`both`) **pulse** a barrier; the **`radarAlert`** event drives a non-barrier **indicator lamp**
+(blink + camera-lock) on a spare relay. The entry button's **12 V light** is the canonical alert
+relay, a 3-state indicator that combines a **[[hikvision-radar|radar]]** trigger input with the
+**camera "car in zone"** signal:
 
-| Radar input | Camera (lane entry busy) | Button light |
+| Trigger input (radar) | Camera (lane entry busy) | Alert lamp |
 | --- | --- | --- |
-| detecting | **free** — no car confirmed | **BLINK** (~1 Hz) |
-| detecting | **busy** — camera confirms a car | **SOLID on** |
-| clear | — | **OFF** |
+| active | **free** — no car confirmed | **BLINK** (~1 Hz) |
+| active | **busy** — camera confirms a car | **SOLID on** |
+| inactive | — | **OFF** |
 
 It is a **disagreement indicator**: the radar sees *something* but the camera hasn't confirmed a
 real vehicle → blink (attention / "pull forward"); both agree → solid; nothing there → off.
 
+Because it's just another relay row, a controller can carry **several** alert relays (e.g. R3 and a
+future R4), each with its own trigger input — no new config shape, no code change.
+
 ## Signals
 
-- **Radar** = the presence input edge on the entry relay (`relays[].presenceInput`, the same edge
-  the [[entry-double-press|one-car-one-ticket]] gate observes — so the lamp and the gate always
-  agree on "a car is here").
-- **Camera "car in zone"** = the existing **[[lpr-camera|lane status]]** (`LaneStatusEvent` entry
-  busy/free, from camera vehicle detection). Already advisory; already drives the booth's barrier
-  lights. No new camera plumbing.
+- **Trigger** = the alert relay's own `triggerInput` edge (the [[hikvision-radar|radar]]). When
+  unset, it falls back to the controller's entry-relay `presenceInput` — the same edge the
+  [[entry-double-press|one-car-one-ticket]] gate observes, so the lamp and the gate agree on "a car
+  is here".
+- **Lock (camera "car in zone")** = the existing **[[lpr-camera|lane status]]** (`LaneStatusEvent`,
+  from camera vehicle detection). Already advisory; already drives the booth's barrier lights. Each
+  lamp picks **which lane's camera** locks it via `relays[].lockLane: "entry"|"exit"` (default
+  entry) — so an **exit radar's lamp locks on the EXIT camera**, not the entry one. (Lane-busy is the
+  only lock *kind* wired today; the model leaves room for others later.)
 
 ## Config
 
-A controller-level `config.buttonLight = { relay, blinkOnMs?, blinkOffMs? }` (the operator picks a
-**spare** relay — not a barrier relay; the setup UI warns if it overlaps one). Blink defaults to
-500 ms / 500 ms.
+An alert lamp is a `config.relays[]` row with `direction: "radarAlert"`, carrying
+`{ relay, triggerInput?, blinkOnMs?, blinkOffMs? }`. No separate `buttonLight` block (that was the
+pre-2026-06-28 shape — barriers and the lamp were two different configs; now they're one list).
+Blink defaults to 500 ms / 500 ms. The operator picks a **spare** relay (an alert relay never opens
+a barrier; every barrier resolver skips `radarAlert` rows).
 
 ## Implementation
 
-`apps/server/src/button-light.ts` — `ButtonLightController` subscribes to `deviceEvents.onInput`
-(radar) + `onLaneStatus` (camera), computes the target state per controller, and drives the lamp via
-a **device-agnostic aux-output** capability.
+`apps/server/src/button-light.ts` — `ButtonLightController` reads the `radarAlert` rows
+(`alertRelaysOf()` in `device-resolve.ts`), subscribes to `deviceEvents.onInput` (radar) +
+`onLaneStatus` (camera), computes the target state **per lamp** (keyed `controllerId:relay`, so
+several alert relays on one controller are independent), and drives each lamp via a **device-agnostic
+aux-output** capability.
 
 - **Aux-output capability.** `AuxOutputDevice { setAux(channel, on) }` on the device interface (the
   Dingtian driver implements it as a latch). Business logic drives the lamp through this — **never**
@@ -68,8 +81,12 @@ a **device-agnostic aux-output** capability.
 ## Status
 
 Built 2026-06-24 for the first booth (button I1, radar I2, lamp on a spare relay); the serialized-send
-+ hot-reload fixes landed the same day after the lamp stuck on/off on hardware. Covered by
-`apps/server/src/button-light.test.ts` (the truth table, blink toggling asserted on the device's
-*confirmed* state, fail-OFF, de-dupe, and a lamp-added-after-start reconcile case).
++ hot-reload fixes landed the same day after the lamp stuck on/off on hardware. **Reframed
+2026-06-28**: the dedicated `config.buttonLight` block was folded into the unified `relays[]` list as
+a `radarAlert` event-relay (carrying its own `triggerInput`), so the operator can add arbitrary
+event-driven blinkers (e.g. R4) without code changes; the 3-state machine itself is unchanged.
+Covered by `apps/server/src/button-light.test.ts` (the truth table, blink toggling asserted on the
+device's *confirmed* state, fail-OFF, de-dupe, lamp-added-after-start reconcile, and two independent
+alert relays on one controller).
 Related: [[hikvision-radar]], [[entry-double-press]], [[lpr-camera]], [[dingtian-relay]],
-[[barrier-not-a-door]].
+[[entry-exit-points]], [[barrier-not-a-door]].