[JohanBendz]

First implementation batch from the consolidated backlog

Implements the physically interviewed MOWE MW815R _TZ3000_o9f2zqln / TS0207 (original #473, canonical #1288) as a separate exact driver. This is standard IAS Zone 0x0500 + Power Configuration 0x0001 only. It must NOT be folded into the existing solar RB-SRAIN01 rain_sensor with proprietary EF00/DP105.

• Isolated rain_sensor_mowe Compose/runtime; IAS wet/dry, IAS low battery, battery percentage report in ZCL half-percent units; on-request IAS Zone enrollment response; no unsolicited startup reads/writes.
• Unknown actual cell type/count represented with temporary energy.batteries: ["OTHER"]; no assumed rain intensity/lux/solar data.
• Exact-identity regression and mocked real-runtime tests, generated manifest/index, public 0.4 physical acceptance row and Test changelog.
• Reuses generic existing flood-sensor artwork using Git blob copies. No legacy driver/light/shared Zigbee changes.

Before Test: CI generation, index, contract/tests, publish validation, diff review. During public 0.4 Test: verify IAS enrollment, actual wet→dry→wet→dry, alarm/Flow, battery and restart/rejoin on THIS fingerprint. This draft must not imply physical acceptance or change frozen 0.3.1/PR #1470.

Refs: #1288, #473, #1469.