OPT-09: the weights parameter nothing ever passed, and what it cannot do

`allocator.plan()` has taken a `weights` argument since ALLOC-01 and NOTHING
had ever passed one - main.py called `resolve()` without it and the arbiter
defaulted it to 1.0 per unit - so the site target was split 50/50 regardless
of what either pack could do. Two things now feed it, and they are different
kinds of thing:

  * a `pack` UNIT claim at P_SAFETY that CLOSES a unit's envelope at its own
    `bms_soc_floor` or at 100 % - a PERMISSION, obeyed absolutely, so an empty
    pack is not asked to discharge and its share goes to the sibling;
  * SoC-aware weights by ENERGY headroom in kWh - a PREFERENCE, which
    `_fill()`'s last-resort pass will override the moment the sibling saturates.

Measured (test_packshare.py part 8): at a load one pack cannot cover, the
weighted arm and the shipped arm command the IDENTICAL watts into an empty pack
and deliver the IDENTICAL watts. Only the envelope stops the ask, and what it
buys is not delivery - it is a reported `unmet_w` where the record used to read
impeccable. Weights are a comfort choice for STABILITY and NOT for DELIVERY.

Also: an optional per-entry `capacity_kwh` (schema change, all-or-nothing across
the roster, rule 9 refuses a partial one); per-pack arbitrage sizing, with the
sell side's no-op stated rather than hidden; and a 0 W trade refused by name,
because a 0 W arbitrage claim is a park order that outranks the loop.

SAFETY-42 and this card meet at one hazard from opposite sides - OPT-09 stops
the site ASKING a pack whose SoC says it cannot deliver, SAFETY-42 alarms when a
pack that said it could does not - and its end-to-end fixture moved as a result.
Its finding is unchanged and is now stated on the two quantities its rejected
discriminator actually reads.

Not filed at all at a roster of one: at N=1 every source routes to the site, so
the interval would bound the SITE TARGET, and SAFETY-25's decided Option A
stands untouched on the live install.

⚠️ INVERTER B DOES NOT EXIST. Its 4600 W / 20.48 kWh / 10 % are FROM DATASHEET
AND SERIAL, and `sim/plantsim.py`'s INVERTER_B is inverter A copied
(`measured=False`), so every two-inverter figure here is arithmetic or two
copies of A. No hardware was touched.

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

goodwe_controller/test_validate.py

@@ -264,6 +264,53 @@ check("...but the ENTRY is refused all the same, by rule 9 and not by the "
                                                    "setpoint_entity": "  "}]),
                                   -5000, 5000), "has no setpoint_entity"))
 
+# --- OPT-09: `capacity_kwh`, which is OPTIONAL but not PARTIAL ---------------
+# ⚠️ RULE 9 GAINED TWO CLAUSES AND BOTH REFUSE A CONFIG THAT WOULD OTHERWISE
+# RUN, which is the bar every clause of this rule is held to. A capacity that is
+# not a usable number is a pack the split would quietly stop preferring while
+# the operator can see a value in the box; a capacity on SOME entries is worse,
+# because `packshare.weights()` answers "no opinion" for the WHOLE roster in
+# that case - so every key the operator filled in does exactly nothing and
+# nothing says so.
+def _with_cap(*caps):
+    o = {k: v for k, v in _PER_INVERTER_OK.items()}
+    o["inverters"] = [dict(e) for e in _PER_INVERTER_OK["inverters"]]
+    for entry, cap in zip(o["inverters"], caps):
+        if cap is not None:
+            entry["capacity_kwh"] = cap
+    return o
+
+
+check("a roster stating a capacity on EVERY entry is accepted - and the two "
+      "differ (15.36 / 20.48, FROM DATASHEET for B), because a fixture whose "
+      "two per-unit numbers are equal cannot show a check reading the wrong "
+      "unit's",
+      validate_startup_config(_with_cap(15.36, 20.48), -5000, 5000) == [])
+check("...and a roster stating NONE is accepted too, which is what OPTIONAL "
+      "means: the add-on has no opinion about the split and every unit weighs "
+      "1.0, exactly as it did before this card",
+      validate_startup_config(_with_cap(None, None), -5000, 5000) == [])
+check("a capacity that is not a usable number of kWh is REFUSED, and the "
+      "refusal names the entry - zero, negative and a word alike",
+      all(why(validate_startup_config(_with_cap(15.36, bad), -5000, 5000),
+              "capacity_kwh") for bad in (0, -3, "twenty", 0.0)))
+check("⚠️ AND A PARTIAL ROSTER IS REFUSED - stated on one entry and left empty "
+      "on the other. It is the clause that costs an operator something, and it "
+      "is the one worth having: a pack measured in kWh beside a sibling "
+      "weighing a dimensionless 1.0 is not a comparison, so the key would "
+      "silently change nothing at all",
+      why(validate_startup_config(_with_cap(15.36, None), -5000, 5000),
+          "not PARTIAL")
+      and why(validate_startup_config(_with_cap(None, 20.48), -5000, 5000),
+              "not PARTIAL"))
+check("...and the refusal names WHICH entry is which, because an operator with "
+      "three inverters told 'one of them is wrong' is sent to the wrong "
+      "cupboard",
+      why(validate_startup_config(_with_cap(15.36, None), -5000, 5000),
+          "inverter-a")
+      and why(validate_startup_config(_with_cap(15.36, None), -5000, 5000),
+              "inverter-b"))
+
 # --------------------------------------------------------------------------- #
 print("3. a meter that can never read")
 # ⚠️ These predicates belong to p1.validate_meter_options(), which build_source()