docs(alphaess): add curtailment firmware prerequisite and DC curtailment toggle docs AlphaESS Smile5 users were reporting curtailment had no physical effect. Root cause: the inverter firmware has a separate Modbus export-control setting that must be enabled before 0x0800 writes are enforced. Without it the register changes but PV output is unaffected. Adds a dedicated AlphaESS.md page covering setup, how curtailment works, the firmware prerequisite steps, limitations, and a troubleshooting section. Updates Battery-System-Setup.md AlphaESS section with: - Firmware prerequisite callout block with step-by-step instructions - Step 4 in setup noting the DC curtailment toggle and its dependency on the firmware setting - Inline troubleshooting for the most common failure path

bolagnaise committed Apr 26, 2026