feat(hardware): initial hardware documentation, 3D models, and ESP32 client code

- Add initial versions of hardware bills of materials (BOM v1-v4), shopping lists, plan, and assembly guides.
- Add STL models for 3D-printing the 1/27 scale OpenRC F1 car parts.
- Add Blender 3D project files (.blend) and camera renders of the car design iterations.
- Add ESP32 client firmware source (client.ino) for handling video streaming and car controls.
- Ignore Blender backup files (*.blend1, *.blend2) and IDE directories.

hardware/BOM_v2.json

@@ -0,0 +1,53 @@
+{
+  "chassis": {
+    "scale": "1/27 Compact",
+    "wheelbase_mm": 102,
+    "track_front_mm": 58,
+    "track_rear_mm": 60,
+    "deck_mm": [80, 135, 2.5],
+    "deck_material": "PETG",
+    "ground_clearance_mm": 7,
+    "shocks": "PN Racing Mini-Z oil-filled, ~30mm"
+  },
+  "drivetrain": [
+    {"slot": "Front wheels", "model": "PN Racing PN-WS-F1 (или GL Racing F1 front)", "size_mm": "Ø25×8", "qty": 2, "search_query": "PN Racing F1 front wheel 25mm Mini-Z", "price_usd": 8.0},
+    {"slot": "Rear wheels",  "model": "PN Racing PN-WS-R1", "size_mm": "Ø28×11", "qty": 2, "search_query": "PN Racing R1 rear wheel 28mm Mini-Z", "price_usd": 8.0},
+    {"slot": "Front bearing","model": "684ZZ (4×9×4)", "qty": 2, "search_query": "684ZZ bearing 4x9x4", "price_usd": 1.5},
+    {"slot": "Rear bearing", "model": "693ZZ (3×8×4)", "qty": 2, "search_query": "693ZZ bearing 3x8x4", "price_usd": 1.0},
+    {"slot": "Dogbones",     "model": "PN Racing PN-DB-30 steel", "qty": 2, "search_query": "PN Racing dogbone drive shaft Mini-Z", "price_usd": 4.0},
+    {"slot": "Pinion",       "model": "M0.3 10T steel", "qty": 1, "search_query": "M0.3 pinion 10T steel Mini-Z", "price_usd": 1.5},
+    {"slot": "Spur gear",    "model": "M0.3 56T delrin", "qty": 1, "search_query": "M0.3 spur gear 56T Mini-Z", "price_usd": 1.5},
+    {"slot": "Motor",        "model": "RC0820 brushless 8500KV (для 2S)", "size_mm": "Ø8×20", "voltage": "2S", "search_query": "RC0820 brushless motor 8500KV", "price_usd": 6.0},
+    {"slot": "ESC",          "model": "Hobbywing Quicrun WP 1040-BR", "size_mm": "24×16×6", "current": "40A", "waterproof": true, "search_query": "Hobbywing Quicrun WP 1040-BR 2S", "price_usd": 18.0},
+    {"slot": "Servo",        "model": "PN Racing PN-SRV-001 Mini-Z", "size_mm": "22×11×20", "torque": "1.5kg", "search_query": "PN Racing PN-SRV-001 servo Mini-Z", "price_usd": 9.0},
+    {"slot": "Battery",      "model": "2S LiPo 300mAh 50C XT30", "size_mm": "35×20×12", "search_query": "2S 300mAh 50C LiPo XT30", "price_usd": 6.0},
+    {"slot": "Shocks",       "model": "PN Racing PN-SHK-30 oil-filled Mini-Z", "qty": 4, "search_query": "PN Racing Mini-Z oil shock 30mm", "price_usd": 14.0}
+  ],
+  "fpv": [
+    {"slot": "FPV Camera",   "model": "Eachine C01 PRO 1200TVL", "size_mm": "14×14×16", "search_query": "Eachine C01 PRO 1200TVL FPV camera", "price_usd": 12.0},
+    {"slot": "VTX",          "model": "Eachine TX01S 5.8GHz 25mW", "size_mm": "14×11×3", "search_query": "Eachine TX01S 25mW VTX", "price_usd": 9.0},
+    {"slot": "VTX antenna",  "model": "Pagoda RHCP 5.8GHz stubby", "search_query": "Pagoda RHCP 5.8GHz antenna stubby", "price_usd": 2.0},
+    {"slot": "VRX (PC side)","model": "Eachine ProDVR 5.8GHz USB", "search_query": "Eachine ProDVR 5.8GHz USB receiver", "price_usd": 22.0},
+    {"slot": "VRX antenna",  "model": "RHCP 5.8GHz panel", "search_query": "5.8GHz RHCP panel antenna FPV", "price_usd": 5.0}
+  ],
+  "agent": [
+    {"slot": "MCU",          "model": "ESP32-S3-WROOM-1 DevKitC-1", "search_query": "ESP32-S3 DevKitC-1 N8R2", "price_usd": 6.0},
+    {"slot": "IMU",          "model": "GY-521 MPU-6050", "search_query": "GY-521 MPU-6050 module", "price_usd": 1.5},
+    {"slot": "Buck 5V",      "model": "Mini-360 DC-DC step-down", "search_query": "Mini-360 DC-DC buck converter 5V", "price_usd": 1.0}
+  ],
+  "body": [
+    {"slot": "Body shell",   "model": "PN Racing F1 Lexan 0.5mm (или Tamiya F103)", "search_query": "PN Racing F1 lexan body 1/27 Mini-Z", "price_usd": 18.0},
+    {"slot": "Body posts",   "model": "Custom PETG", "note": "print self", "price_usd": 0.0},
+    {"slot": "Bumpers",      "model": "Custom TPU 95A", "note": "print self", "price_usd": 0.0}
+  ],
+  "crepeage": [
+    {"slot": "M2 screws (assorted)", "search_query": "M2 screw kit Mini-Z RC", "price_usd": 4.0},
+    {"slot": "M3 screws for bumpers","search_query": "M3x8 button head screw TPU", "price_usd": 2.0}
+  ],
+  "totals": {
+    "per_car_usd": 156.5,
+    "4_cars_usd": 626.0,
+    "track_infra_usd": 200.0,
+    "grand_total_usd": 826.0
+  }
+}