Remove SQLite from version 0.1 scope

[Hrabovszki1023]

What changed

• remove SQLite and durable inventory persistence from the Version 0.1 contract
• define the live Pylontech system as the authoritative inventory source
• keep missing modules only in runtime memory and rediscover after restart
• align architecture, implementation plan, README and test strategy

Why

The service already receives module order, positions, barcodes, firmware and
measurements from the battery system. Durable inventory history is not required
for operation and would add unnecessary state and deployment complexity.

Verification

• git diff --check
• repository-wide search for obsolete SQLite and restart-persistence requirements

Documentation-only change; application tests were not required.