PKG-12: bump 0.8.0 -> 0.9.0, so the five merges behind it can actually ship

⚠️ MINOR FOR NEW FUNCTIONALITY, NOT FOR A BREAK, AND THAT DISTINCTION IS
CHECKED RATHER THAN ASSERTED. PKG-07 was minor because a config that started on
0.7.0 could be REFUSED on 0.8.0. Nothing of that kind is true here:

  - `options:` and `schema:` hold 71 top-level keys on both 06661c5 and HEAD.
    The one schema addition is a PER-ENTRY key, `capacity_kwh: float(0.1,200)?`,
    and the trailing `?` makes it OPTIONAL.
  - An unmodified 0.8.0-era config validates clean on 0.9.0. Measured through
    the shipped validator on both the flat single-inverter shape the reference
    install runs and an N=2 roster with no `capacity_kwh` on any entry: 0
    problems each.
  - OPT-09's two new refusals fire only on configs that USE the new key - an
    unparseable value, or the key stated on one entry and left empty on another.
    Neither can reach a config written before the key existed.

PKG-07's first draft justified its bump with an invented compatibility break and
review caught it. This one states what was measured, and the measurement says
existing installs upgrade untouched.

Contents since 0.8.0 (`06661c5`): UX-02 (`3d29993`), OPT-09 (`fdb3b69`),
PKG-09 (`fcaa724`).

⚠️ THE VERSION WENT UNBUMPED FOR THE THIRD TIME IN THREE DAYS - PKG-06 six
merges, PKG-07 six, this one five - and this time PKG-09's own tool caught it
during PKG-09's review rather than a person. The changelog carries OPT-09's
disclosed N=2 detection regression and points at the pre-deploy check.

⚠️ STILL NOT DONE, AND STILL NOT DOABLE FROM HERE: the live options have not
been checked against this version's validator. The gate reports exit 2 - NOT
CLEARED - rather than clearing, which is correct. Export the options from the
Supervisor and re-run before `ha apps update`.

Suite: 26 files, all pass.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU

goodwe_controller/config.yaml

@@ -1,5 +1,5 @@
 name: GoodWe RS485 Controller
-version: "0.8.0"
+version: "0.9.0"
 slug: goodwe_controller
 description: >-
   Drives a GoodWe ES/BP battery inverter over RS485 by emulating its smart