SMA-10: two idle states, hold 0 W or hand the inverter back

A driver now says whether its release() hands the inverter back
(Driver.hands_back; GoodWe is False, so release() stays write(0) and the
Controller never calls it). command_site_release() sits next to
command_site_zero(): the Stop button and shutdown() (so SIGTERM, restart,
control task death and a late config refusal) hand a hand-back unit back,
once, and zero every other unit as before. Safety stops and refusals still
hold 0 W for every unit. Shadow mode releases a hand-back unit. After a
release nothing is written to the unit (heartbeat and cycle included) until
control starts again. release() is bounded by RELEASE_BUDGET_S (= the write
budget), runs concurrently per unit, and a raising or hanging release on one
unit does not stop the others.

The "set to 0 W" sentences for Stop, restart, shadow mode and the stopped
banner are built from the roster (app/handback.py, EN and NL, words from the
driver); a GoodWe-only roster keeps every old literal. A handed-back unit
shows "Back under <its control>" on Home.

Existing test edited: test_messages.py (two classification entries for the
CRITICAL line that moved into a roster builder, and the new release bound).

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

goodwe_controller/app/drivers.py

@@ -77,7 +77,13 @@ class Driver:
     writer_key = ""
     #: the brand word the per-driver sentences and device names use
     brand = ""
-    #: per-driver sentences (SMA-10 and later). Empty until a caller needs one.
+    #: SMA-10. Does `release()` give the inverter BACK to something that steers
+    #: it by itself (SMA energy management)? False: `release()` is `write(0)`,
+    #: the add-on goes on holding 0 W, and the Controller never calls it.
+    hands_back = False
+    #: per-driver sentences. A driver that hands back says whose control the
+    #: unit returns to: `{"back": "SMA control", "back_nl": "de sturing van SMA"}`
+    #: ("goes back to SMA control"). Missing words fall back to a plain phrase.
     words: dict = {}
     #: how long all-rejected writes last before the unit stops being live
     link_stale_s = GOODWE_LINK_STALE_S
@@ -145,7 +151,13 @@ class Driver:
         raise NotImplementedError
 
     async def release(self) -> bool:
-        """Stop steering this inverter. For a driver with nothing better, 0 W."""
+        """Stop steering this inverter. For a driver with nothing better, 0 W.
+
+        SMA-10. Only a driver with `hands_back = True` has this called by the
+        Controller, and only when the add-on goes away (Stop, shutdown, restart,
+        task death) or sits in shadow mode. After it the Controller writes
+        nothing more to the unit until control starts again. A safety stop is
+        never a release: that is `write(0)`."""
         return await self.write(0.0)
 
     async def probe(self) -> Probe:
@@ -159,7 +171,8 @@ class GoodWeEsphomeDriver(Driver):
     A transcription of what `main.py` and `selfconfig.py` did inline: `limits()`
     is `hass.limits(setpoint)`, `read()` is `hass.number(soc)` then
     `hass.number(batt, invert)`, `write()` is `hass.set_number(setpoint, w)`.
-    `release()` is `write(0)`: the board's own watchdog is what hands back.
+    `release()` is `write(0)` and `hands_back` is False: the board's own watchdog
+    is what hands back, so after Stop the unit keeps its 0 W write and heartbeat.
     """
 
     name = DEFAULT_DRIVER