Tie points to locator serial numbers and store receiver telemetry

Field setups often relay through a phone/gateway that owns the MQTT
connection, so the publishing credential and the instrument are now
separate concepts:

- Points messages carry a "serial" identifying the locator receiver;
  unknown serials are auto-registered as devices in the publisher's
  org (name "Locator <serial>"). Device.mqttUsername is now optional
  and serialNumber is unique per org.
- LocatePoint gains standard receiver telemetry: frequencyHz,
  currentMa, signalDb, gainDb, locateMode (PEAK/NULL/BROAD_PEAK/SONDE),
  phaseDeg, compassDeg, distortionPct, plus GPS quality columns
  vAccuracy, satellites, hdop. All optional; raw payload still kept.
- Migration hand-edited to preserve the generated geom column and its
  GIST index (Prisma diff wanted to drop both).
- REST create/point DTOs, map tooltips, job-detail latest-point
  readout, devices settings form, seed, and the sample publisher all
  carry the new fields.
- Added .dockerignore for backend/web: COPY . . was clobbering the
  image's freshly generated Prisma client with the host's stale
  node_modules, breaking image builds after schema changes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/src/ingest/dto/mqtt-messages.dto.ts

@@ -1,4 +1,4 @@
-import { GpsFixType, UtilityType } from '@prisma/client';
+import { GpsFixType, LocateMode, UtilityType } from '@prisma/client';
 import { Type } from 'class-transformer';
 import {
   ArrayMaxSize,
@@ -54,6 +54,61 @@ export class MqttPointDto {
   @IsInt()
   seq?: number;
 
+  // GPS quality
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  vAcc?: number;
+
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  sats?: number;
+
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  hdop?: number;
+
+  // Locator receiver telemetry
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  freqHz?: number;
+
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  currentMa?: number;
+
+  @IsOptional()
+  @IsNumber()
+  signalDb?: number;
+
+  @IsOptional()
+  @IsNumber()
+  gainDb?: number;
+
+  @IsOptional()
+  @IsEnum(LocateMode)
+  mode?: LocateMode;
+
+  @IsOptional()
+  @IsNumber()
+  phaseDeg?: number;
+
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  @Max(360)
+  compassDeg?: number;
+
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  @Max(100)
+  distortionPct?: number;
+
   @IsDateString()
   ts: string;
 }
@@ -69,6 +124,13 @@ export class MqttPointsMessageDto {
   @MaxLength(64)
   ticket?: string;
 
+  // Locator receiver serial number; the publisher (MQTT credential) may be a
+  // phone/gateway relaying for one or more locators. Auto-registered on first sight.
+  @IsOptional()
+  @IsString()
+  @MaxLength(64)
+  serial?: string;
+
   @IsArray()
   @ArrayMinSize(1)
   @ArrayMaxSize(500)