feat: add GPS trip detection, history panel, and playback (#23)

Auto-detect trips from GPS data (5-min idle threshold), pre-compute
OSRM routes on trip completion, add trip history side panel with
toggleable trips, and animated trip playback with speed controls.

- Add GpsTrip model with TripStatus enum and migration
- Trip detection in syncPositions cron (start on movement, end on idle)
- Trip finalization with OSRM route matching and stats computation
- API endpoints: list/detail/active/merge/backfill trips
- Stats tab overhaul: trip list panel + map with colored polylines
- Trip playback: animated marker, progressive trail, 1x-16x speed
- Live map shows active trip trail instead of full day history
- Historical backfill from existing GPS location data

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/prisma/migrations/20260208165115_add_gps_trips/migration.sql

@@ -0,0 +1,34 @@
+-- CreateEnum
+CREATE TYPE "TripStatus" AS ENUM ('ACTIVE', 'COMPLETED', 'PROCESSING', 'FAILED');
+
+-- CreateTable
+CREATE TABLE "gps_trips" (
+    "id" TEXT NOT NULL,
+    "deviceId" TEXT NOT NULL,
+    "status" "TripStatus" NOT NULL DEFAULT 'ACTIVE',
+    "startTime" TIMESTAMP(3) NOT NULL,
+    "endTime" TIMESTAMP(3),
+    "startLatitude" DOUBLE PRECISION NOT NULL,
+    "startLongitude" DOUBLE PRECISION NOT NULL,
+    "endLatitude" DOUBLE PRECISION,
+    "endLongitude" DOUBLE PRECISION,
+    "distanceMiles" DOUBLE PRECISION,
+    "durationSeconds" INTEGER,
+    "topSpeedMph" DOUBLE PRECISION,
+    "averageSpeedMph" DOUBLE PRECISION,
+    "pointCount" INTEGER NOT NULL DEFAULT 0,
+    "matchedRoute" JSONB,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "gps_trips_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "gps_trips_deviceId_startTime_idx" ON "gps_trips"("deviceId", "startTime");
+
+-- CreateIndex
+CREATE INDEX "gps_trips_status_idx" ON "gps_trips"("status");
+
+-- AddForeignKey
+ALTER TABLE "gps_trips" ADD CONSTRAINT "gps_trips_deviceId_fkey" FOREIGN KEY ("deviceId") REFERENCES "gps_devices"("id") ON DELETE CASCADE ON UPDATE CASCADE;

backend/prisma/schema.prisma

@@ -405,6 +405,7 @@ model GpsDevice {
 
   // Location history
   locationHistory   GpsLocationHistory[]
+  trips             GpsTrip[]
 
   createdAt         DateTime  @default(now())
   updatedAt         DateTime  @updatedAt
@@ -434,6 +435,45 @@ model GpsLocationHistory {
   @@index([timestamp]) // For cleanup job
 }
 
+enum TripStatus {
+  ACTIVE        // Currently in progress
+  COMPLETED     // Finished, OSRM route computed
+  PROCESSING    // OSRM computation in progress
+  FAILED        // OSRM computation failed
+}
+
+model GpsTrip {
+  id                String     @id @default(uuid())
+  deviceId          String
+  device            GpsDevice  @relation(fields: [deviceId], references: [id], onDelete: Cascade)
+
+  status            TripStatus @default(ACTIVE)
+
+  startTime         DateTime
+  endTime           DateTime?
+  startLatitude     Float
+  startLongitude    Float
+  endLatitude       Float?
+  endLongitude      Float?
+
+  // Pre-computed stats (filled on completion)
+  distanceMiles     Float?
+  durationSeconds   Int?
+  topSpeedMph       Float?
+  averageSpeedMph   Float?
+  pointCount        Int        @default(0)
+
+  // Pre-computed OSRM route (stored as JSON for instant display)
+  matchedRoute      Json?      // { coordinates: [lat,lng][], distance, duration, confidence }
+
+  createdAt         DateTime   @default(now())
+  updatedAt         DateTime   @updatedAt
+
+  @@map("gps_trips")
+  @@index([deviceId, startTime])
+  @@index([status])
+}
+
 model GpsSettings {
   id                    String   @id @default(uuid())