DOC-8: say EMS port, not meter bus

The add-on is wired to the inverter's RS485 port labelled EMS. Reword
README, DOCS, config description, field guide source and HTML. The HA
manufacturer string is left unchanged: test_mqtt pins it byte for byte.

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -1,8 +1,8 @@
 # GoodWe RS485 Controller — Home Assistant add-on repository
 
 Replaces a GoodWe battery inverter's vendor controller with a local one: holds
-net grid exchange at zero by emulating the inverter's smart meter over RS485,
-and runs the monthly battery maintenance cycle the vendor box was doing.
+net grid exchange at zero by sending the inverter a grid reading over its RS485
+EMS port, and runs the monthly battery maintenance cycle the vendor box was doing.
 
 ```
 repository.yaml            add-on repository metadata
@@ -118,17 +118,17 @@ the platform tag:
 
 | tag | platform | verdict |
 |---|---|---|
-| `ESU EMU ESA BPS BPU EMJ IJL` | 105 — ES/EM/BP, AA55-era meter bus | **supported** |
+| `ESU EMU ESA BPS BPU EMJ IJL` | 105 — ES/EM/BP, AA55-era | **supported** |
 | `SPB SPN` | 745 — SBP **G2** (`GW…-SBP-20`) | no |
 | `ESN ESC` | 745 — ES **G2** (`GW…-ES-20`) | no |
 | `ETU EHU BTU …` | 205/745/753 — ET/EH/BT hybrids | no |
 | `SDT DST MSU NSU …` | PV-only inverters — no battery to control | no |
 
-A "-20" or "G2" suffix means a different platform with a different meter
+A "-20" or "G2" suffix means a different platform with a different
 protocol. The tags come from the `goodwe` library's `PLATFORM_105_MODELS`, which
 is also what Home Assistant's own integration uses to pick a protocol.
 
-- GoodWe **ES / BP family** inverters (AA55 / RS485 meter-bus generation)
+- GoodWe **ES / BP family** inverters (AA55 generation)
 - The protocol is **reverse-engineered**. There is no vendor contract, and a
   firmware change on GoodWe's side could break every installation at once. Say
   so when you sell it.