feat(pos): fleet management module — vehicles, maintenance schedules, alerts

Add full fleet management (Feature 13): database migration for fleet_vehicles,
fleet_maintenance_schedules, and fleet_maintenance_logs tables; REST API blueprint
with CRUD, scheduling, logging, alerts, and stats endpoints; frontend with tabbed
UI (vehicles grid, maintenance schedules, history, overdue alerts); sidebar nav entry.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pos/migrations/v1.3_fleet.sql

@@ -0,0 +1,50 @@
+-- v1.3 Fleet Management tables
+-- Vehicles, maintenance schedules, and maintenance logs
+
+CREATE TABLE IF NOT EXISTS fleet_vehicles (
+    id SERIAL PRIMARY KEY,
+    branch_id INTEGER REFERENCES branches(id),
+    plate VARCHAR(20),
+    vin VARCHAR(17),
+    make VARCHAR(100),
+    model VARCHAR(100),
+    year INTEGER,
+    current_mileage INTEGER DEFAULT 0,
+    fuel_type VARCHAR(20) DEFAULT 'gasolina',
+    color VARCHAR(50),
+    owner_name VARCHAR(200),
+    notes TEXT,
+    is_active BOOLEAN DEFAULT TRUE,
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS fleet_maintenance_schedules (
+    id SERIAL PRIMARY KEY,
+    vehicle_id INTEGER REFERENCES fleet_vehicles(id),
+    maintenance_type VARCHAR(100) NOT NULL,
+    interval_km INTEGER,
+    interval_months INTEGER,
+    last_done_at TIMESTAMPTZ,
+    last_done_km INTEGER,
+    next_due_at TIMESTAMPTZ,
+    next_due_km INTEGER,
+    notes TEXT,
+    is_active BOOLEAN DEFAULT TRUE
+);
+
+CREATE TABLE IF NOT EXISTS fleet_maintenance_logs (
+    id SERIAL PRIMARY KEY,
+    vehicle_id INTEGER REFERENCES fleet_vehicles(id),
+    schedule_id INTEGER REFERENCES fleet_maintenance_schedules(id),
+    maintenance_type VARCHAR(100),
+    mileage_at INTEGER,
+    cost NUMERIC(12,2),
+    parts_used TEXT,
+    employee_id INTEGER REFERENCES employees(id),
+    notes TEXT,
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_fleet_vehicles_plate ON fleet_vehicles(plate);
+CREATE INDEX IF NOT EXISTS idx_fleet_maint_vehicle ON fleet_maintenance_schedules(vehicle_id);
+CREATE INDEX IF NOT EXISTS idx_fleet_logs_vehicle ON fleet_maintenance_logs(vehicle_id);