KiCad PCB Design — RS-485 Temperature/Humidity Sensor

We need a PCB designed in KiCad 8.x for a compact RS-485 sensor node that measures temperature and humidity. Quality, DFM compliance, and proper protection circuits are important.
Board overview:

55 × 30mm, 2-layer FR4, black solder mask, lead-free HASL
MCU: ATtiny1614 (SOIC-14)
Sensor: SHT41 temperature/humidity (DFN 1.5×1.5mm)
Communication: RS-485 half-duplex via MAX3485 transceiver
Connectors: 2× RJ45 (daisy-chain in/out) + 1× JST-SH 4-pin (external sensor port)
Power: 5V input via RJ45 → AMS1117-3.3 LDO → 3.3V
Full protection circuits: reverse polarity (P-MOSFET), PTC fuse, TVS diodes (RS-485 + VCC + UPDI), fail-safe biasing, ferrite bead EMI filter
Thermal isolation between sensor and electronics (routed PCB slot + ground pour keepout)
3-bit solder jumper addressing + termination resistor jumper
UPDI programming via pogo pads + RJ45 pin

Target manufacturer: JLCPCB (turnkey SMT assembly). All outputs must be JLCPCB-compatible.

Required deliverables:

KiCad 8.x project files (schematic + PCB)
Schematic PDF
Gerber + drill files
JLCPCB-format BOM (CSV with LCSC part numbers)
JLCPCB-format pick-and-place file
3D STEP model
DRC + ERC reports (zero errors)